View Code of Problem 120

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