View Code of Problem 120

#include<stdio.h>
main()
{
	int h1,m1,h2,m2,s1,s2,i,j,sum,flag;
	while(scanf("%d:%d",&h1,&m1)!=EOF)
	{
		scanf("%d:%d",&h2,&m2);
		s1=h1*2500+m1;
		s2=h2*2500+m2;
		sum=0;
		for(i=s1;i<=s2;i++)
		{
			flag=0;
			if(i==0||i==1)
				flag=1;
			for(j=2;j<i;j++)
			{
				if(i%j==0)
				{
					flag=1;
					break;
				}
			}
			if(flag==0)sum++;
		}
		printf("%d\n",sum);
	}
}