太简单了

#include <iostream>
using namespace std;
int main(){
int a,s = 0;
cin >> a;
if (a % 3 == 0) cout << "3 ";
else s += 1;
if (a % 5 == 0) cout << "5 ";
else s += 1;
if (a % 7 == 0) cout << "7 ";
else s += 1;
if (s == 3) cout << "n";
return 0;
}