View Code of Problem 120

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
#include<ctype.h>
int main()
{
	int i, j, n, flag;
	int h1, m1, h2, m2;
	int sum1, sum2, temp;
	while (scanf("%d:%d",&h1,&m1)!=EOF)
	{
		scanf("%d:%d", &h2, &m2);
		sum1 = h1 * 2500 + m1;
		sum2 = h2 * 2500 + m2;
		if (sum1 > sum2)
		{
			temp = sum1;
			sum1 = sum2;
			sum2 = temp;
		}
		n = 0;
		for (i = sum1; i <= sum2; i++)
		{
			flag = 0;
			for (j = 2; j*j <= i; j++)
			{
				if (i%j == 0)
				{
					flag = 1;
					break;
				}
			}
			if (flag == 0)
				n++;
		}
		printf("%d\n", n);
	}
	return 0;
}