其实模15就行了

using namespace std;

   int main() {
	int a;
	cin<<a;
	if(a%15==0){
		cout<<"YES";
	}else{
		cout<<"NO";
	}

	return 0;
}

纯属偷懒

#include <bits/stdc++.h> using namespace std;

int main() { long long n; cin >> n; if (n % 3 == 0 && n % 5 == 0) { cout << "YES"; } else { cout << "NO"; } return 0; }

#include <bits/stdc++.h> using namespace std;

int main() { int n; cin >> n; if (n%3==0) { cout << "YES"; } else { cout << "NO"; } return 0; }