View Code of Problem 18

#include<stdio.h>
#include<string.h>

int main(){
	int i;
	double sum,n;
	while(scanf("%lf",&n)!=EOF){
		sum=0;
		if((int)n%2==0){
			sum=(1+n/2-1)*(n/2-1)/2;	
			printf("%0.lf\n",sum*2);
		}else{
			sum=(1+(int)n/2)*((int)n/2)/2+((int)n/2)*((int)n/2-1)/2;
				printf("%0.lf\n",sum);
		}
	}
	return 0;
}