View Code of Problem 120

# include<stdio.h>
# include<math.h>
int f(int t)
{
    int i,flag = 0;
    for(i=2;i<=sqrt(t);++i)
    {
        if(t%i==0)
        {
            flag = 1;
            break ;
        }
    }
    if(flag==0)
    {
        return 1;
    }
    else
    return 0;
}
int main(void)
{
  int h,m,H,M,i,cnt=0;
  while(scanf("%2d:%2d",&h,&m)!=EOF)
  {
    scanf("%2d:%2d",&H,&M);
    for(i=h*2500+m;i<=H*2500+M;++i)
    {
        if(f(i))
        {
            ++cnt;
        }
    }
    printf("%d\n",cnt);
  }
  return 0;
}