View Code of Problem 120

#include<stdio.h>
#include<string.h>
#include<math.h>
int main()
{
	char a[10], b[10];
	while (scanf("%s",a)!=EOF)
	{
		scanf("%s", b);
		int h1, h2, m1, m2;
		h1 = (a[0] - '0') * 10 + (a[1] - '0');
		h2 = (b[0] - '0') * 10 + (b[1] - '0');
		m1 = (a[3] - '0') * 10 + (a[4] - '0');
		m2 = (b[3] - '0') * 10 + (b[4] - '0');
		int start = h1 * 2500 + m1;
		int end = h2 * 2500 + m2;
		int count = 1;
		for (int i = start; i <= end;  i++)
		{
			int flag = 1;
			for (int j = 2; j <= sqrt(i); j++)
			{
				if (i%j == 0)
				{
					flag = 0;
					break;
				}
			}
			if (flag) count++;
		}
		printf("%d\n", count-1);
	}
	return 0;
}