View Code of Problem 18

#include <iostream>
using namespace std;
 
int main(){
    int n;
    while(~scanf("%d",&n)){  //分两半算下 
    	int i = n/2;
    	if(n<3)cout<<0;
    	else if(n %2 == 0)cout<<(i-1)*i;
    	else cout<<((i-1)*i/2)+((i+1)*i/2); 
		cout<<endl; 
	}
    return 0;
}