#include <iostream>
#include <cmath>
int func (int n){
    int r=0;
    while (n){
        r+=n%10;
        n/=10;
    }
    return r;
}
using namespace std;
int main (){
    int n, r;
    cin >> n;
    while (r>=pow(10,n-1)-1){
        r=pow(10,n-1)-1;
        int j=func(r);
        if (j%3==0){
            cout<<j;
            break;
        }
        r++;
    }
    return 0;
}