区域内点的个数

#include <stdio.h>  
int main()  
{  
    double x1,x2;  
    double y1,y2;  
    int n;  
    double x,y;  
    int num = 0;  
    while(~scanf("%d",&n))  
    {  
        num = 0;  
        scanf("%lf%lf",&x1,&y1);  
        scanf("%lf%lf",&x2,&y2);  
        while(n--)  
        {  
            scanf("%lf%lf",&x,&y);  
            if(x > x1 && x < x2 && y > y1 && y < y2)  
                num++;  
        }  
        printf("%d\n",num);  
    }  
    return 0;  
}