View Code of Problem 120

# include<stdio.h>
# include<math.h>
int f(int i)
{
    int t,flag = 0;
    for(t=2;t<=sqrt(i);++t)
    {
        if(i%t==0)
        {
            flag = 1;
            break;
        }
    }
    if(flag)
    {
        return 0;
    }
    else
    return 1;
}
int main(void)
{
  int h,m,i,H,M,cnt=0;
  while(scanf("%2d:%2d",&h,&m)!=EOF)
  {
    scanf("%2d:%2d",&H,&M);
    int sum = 0;
    sum  = (H*60+M)-(h*60+m);
    for(i=0;i<=sum;++i)
    {
        if(m>=60)
        {
            m = m-60;
            ++h;
        }
        if(f(h*2500+m))
        {
            ++cnt;
        }
        ++m;
    }
    printf("%d",cnt);
  }
  return 0;
}

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