diff --git a/Makefile b/Makefile
index 61636ef..c101bc8 100644
--- a/Makefile
+++ b/Makefile
@@ -1,16 +1,16 @@
 CFLAGS=-Wall -I munit -ggdb
 unittest_obj=munit/munit.o
 
-all: str_bin str_test
+all: aux_bin aux_test
 
-str_test: $(unittest_obj) str_lib.o str_test.o
+aux_bin: aux_bin.o aux_lib.o
 	$(CC) $(CFLAGS) -o $@ $^
 
-str_bin: str_lib.o str_bin.o
+aux_test: $(unittest_obj) aux_lib.o aux_test.o
 	$(CC) $(CFLAGS) -o $@ $^
 
-test: ./str_test
-	./str_test
+test: ./aux_test
+	./aux_test
 
 clean:
-	rm *_bin *.o $(unittest_obj) str_test
+	rm *_bin *.o $(unittest_obj) aux_test
diff --git a/aux_bin.c b/aux_bin.c
new file mode 100644
index 0000000..ba906a6
--- /dev/null
+++ b/aux_bin.c
@@ -0,0 +1,18 @@
+#include <stdio.h>
+#include "aux_lib.h"
+
+#define ARRSZ(arr) (sizeof(arr) / sizeof(arr[0]))
+
+int
+main(int argc, const char *argv[])
+{
+	int n = 5;
+	printf("fibonacci(%d) == %d\n", n, fibonacci(n));
+
+	int arr[] = {1,2,3,4,5};
+
+	bool res = sum_is_odd(arr, ARRSZ(arr));
+	printf("sum_is_odd() == %s\n", res ? "true" : "false");
+
+	return 0;
+}
diff --git a/aux_lib.c b/aux_lib.c
new file mode 100644
index 0000000..469bd42
--- /dev/null
+++ b/aux_lib.c
@@ -0,0 +1,22 @@
+#include "aux_lib.h"
+
+/*
+ * Функция возвращает n-ный элемент последовательности фибоначи
+ */
+int
+fibonacci(int nitem)
+{
+	//YOUR_CODE
+	return 42;
+}
+
+/*
+ * Функция считает сумму элементов массива и возвращает информацию
+ * является ли эта сумма нечётным числом.
+ */
+bool
+sum_is_odd(int *arr, int arrsz)
+{
+	//YOUR_CODE
+	return false;
+}
diff --git a/aux_lib.h b/aux_lib.h
new file mode 100644
index 0000000..bcf878c
--- /dev/null
+++ b/aux_lib.h
@@ -0,0 +1,7 @@
+#pragma once
+#include <stdbool.h>
+
+int fibonacci(int nitem);
+
+bool sum_is_odd(int *arr, int arrsz);
+
diff --git a/aux_test.c b/aux_test.c
new file mode 100644
index 0000000..0de7fbf
--- /dev/null
+++ b/aux_test.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include "munit.h"
+#include "aux_lib.h"
+
+static const MunitSuite test_suite = {
+	//FILL ME
+};
+
+int
+main(int argc, const char *argv[])
+{
+	munit_suite_main(&test_suite, (void *) "string library test", argc, (char * const*) argv);
+	return 0;
+}
+
diff --git a/str_bin.c b/str_bin.c
deleted file mode 100644
index 16b6fea..0000000
--- a/str_bin.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include <stdio.h>
-#include "str_lib.h"
-
-int
-main(int argc, const char *argv[])
-{
-	const char *s1 = "hello";
-	const char *s2 = "ello";
-
-	if (argc > 2) {
-		s1 = argv[1];
-		s2 = argv[2];
-	}
-
-	// binary for manual testing
-	printf("\033[1;30mUse str_test for actual testing\033[0m\n");
-
-	printf("mystrlen(\"%s\") == %d\n", s1, mystrlen(s1));
-	printf("str_idx(\"%s\", \"%s\") == %d\n", s1, s2, mystr_idx(s1, s2));
-	return 0;
-}
diff --git a/str_lib.c b/str_lib.c
deleted file mode 100644
index fa1d7db..0000000
--- a/str_lib.c
+++ /dev/null
@@ -1,23 +0,0 @@
-#include <string.h>
-
-/*
- * Вернуть длину строки.
- * Строки в C -- это массив символов, в конце которого находится нулевой символ ( '\0')
- */
-int
-mystrlen(const char *s)
-{
-	// <YOURCODE>
-}
-
-/*
- * Найти индекс, с которого строка s2 присутствует в строке s1
- * или -1
- */
-int
-mystr_idx(const char *s1, const char *s2)
-{
-	// <YOURCODE>
-	return -1;
-}
-
diff --git a/str_lib.h b/str_lib.h
deleted file mode 100644
index d89a75b..0000000
--- a/str_lib.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#pragma once
-
-int mystrlen(const char *s);
-
-int mystr_idx(const char *s1, const char *s2);
-
diff --git a/str_test.c b/str_test.c
deleted file mode 100644
index 074f9f4..0000000
--- a/str_test.c
+++ /dev/null
@@ -1,67 +0,0 @@
-#include <stdio.h>
-#include "munit.h"
-#include "str_lib.h"
-
-static MunitResult
-test_mystrlen(const MunitParameter params[], void * data)
-{
-	munit_assert_true(mystrlen("")  ==  0);
-	munit_assert_true(mystrlen("333")  ==  3);
-	munit_assert_true(mystrlen("helloworld")  ==  10);
-	return MUNIT_OK;
-}
-
-static MunitResult
-test_mystr_idx(const MunitParameter params[], void * data)
-{
-	munit_assert_true(mystr_idx("", "") == 0);
-	munit_assert_true(mystr_idx("h", "h") == 0);
-	munit_assert_true(mystr_idx("ah", "h") == 1);
-	munit_assert_true(mystr_idx("ah", "hh") == -1);
-	munit_assert_true(mystr_idx("ahh", "hh") == 1);
-	char  *cap = "London is the capital of Great Britan";
-	munit_assert_true(mystr_idx(cap, "python") == -1);
-	munit_assert_true(mystr_idx(cap, "London") == 0);
-	munit_assert_true(mystr_idx(cap, "o") == 1);
-	munit_assert_true(mystr_idx(cap, "is") == 7);
-	return MUNIT_OK;
-}
-
-static MunitResult
-test_mystr_idx_largestr(const MunitParameter params[], void * data)
-{
-	munit_assert_true(mystr_idx("", "LARGE STRING") == -1);
-	munit_assert_true(mystr_idx("ARGE_STRING", "LARGE STRING") == -1);
-	munit_assert_true(mystr_idx("ARGE STRING", "LARGE STRING") == -1);
-	munit_assert_true(mystr_idx("RGE STRING", "LARGE STRING") == -1);
-	return MUNIT_OK;
-}
-
-#define TEST_ITEM(func) {#func, func, NULL, NULL, MUNIT_TEST_OPTION_NONE }
-static MunitTest test_suite_tests[] = {
-	TEST_ITEM(test_mystrlen),
-
-	TEST_ITEM(test_mystr_idx),
-	TEST_ITEM(test_mystr_idx_largestr),
-	//TEST_ITEM(test_pvector_init),
-
-	{ NULL, NULL, NULL, NULL, MUNIT_TEST_OPTION_NONE, NULL }
-};
-
-
-static const MunitSuite test_suite = {
-	(char *) "",
-	test_suite_tests,
-	NULL,
-	1,
-	MUNIT_SUITE_OPTION_NONE
-};
-
-
-int
-main(int argc, const char *argv[])
-{
-	munit_suite_main(&test_suite, (void *) "string library test", argc, (char * const*) argv);
-	return 0;
-}
-