#include <stdio.h>
#include <string.h>
int myatoi(char *s, int l);
int main(int argc, char **argv)
{
	printf("Print your string number\n");
	char s[100]; scanf("%s", s);
	printf("Your converted number is %d\n",  myatoi(s, strlen(s)));
	return 0;
}
int myatoi(char *s, int l) 
{	
	int result = 0;
	int is_pos = 1;
	for(int i=0; i < l; i++)
	{
		if((int)s[i]==45)
			{
				is_pos = -1;
			}
		else
			{
				if((int)s[i] < 48 || (int)s[i] > 57)
				{
					printf("Not a number\n");
					result = 0;
					break;
				}
					result = result * 10 + ((int)s[i] - 48);
			}
	}
	result = result * is_pos;
	return result;
}