View Code of Problem 18

#include<stdio.h>
int main(){
	int n;
	while(scanf("%d",&n)!=EOF){
		int sum = 0;
		
		if(n>=3){
			if(n%2==0) {
				for(int i=n/2;i>0;i--)
				sum = sum+i-1; 
				printf("%d\n",sum*2);
			}else{
				for(int i=n/2;i>0;i--)
				sum = sum+i-1; 
				for(int i=n/2+1;i<=n;i++)
				sum = sum+n-i; 
				printf("%d\n",sum);
			}
	
		}else {
				printf("%d\n",sum);
		}
	}	
}