C :

#include<stdio.h>
int main()
{
    int x;
    scanf("%d",&x);
    if(x%3==0)
        printf("yes");
    else
        printf("no");
        return 0;
}

C++ :

#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin>>n;
	if(n%3==0)cout<<"yes"<<endl;
	else cout<<"no"<<endl;
	return 0;
}

Java :

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		if(n % 3 == 0){
			System.out.println("yes");
		}else{
			System.out.println("no");
		}
		sc.close();
	}

}

Python :

a = int(input())
if a % 3 == 0:
    print('yes')
else:
    print('no')