#include <bits/stdc++.h> using namespace std; int main() { long i,j,k,n,s; while (scanf("%d",&n)!=EOF) { s=0; j=3; while (s!=n) { if (j%3==0 or j%5==0) s++; if (s==n) break; j++; } cout<<j<<endl; } return 0; }