20分求调

#include<bits/stdc++.h>

using namespace std;
long long x;
int main()
{
cin>>x;
if(x%3 == 0)cout<<3<<" ";
else if(x%5 == 0)cout<<5<<" ";
else if(x%7 == 0)cout<<7<<" ";
else cout<<"n";
return 0;
}