#include<bits/stdc++.h>
using namespace std;
int f[500001];
int main() {
    //freopen(".in","r",stdin);
    //freopen(".out","w",stdout);
    int n,l=0;
    cin>>n;
    for(int i=1;l<100001; i++) {
        int j=i;
        if(j%7==0) {
            f[l]=i;
            l++;
        }else{
            while(j!=0) {
                if(j%10==7) {
                    f[l]=i;
                    l++;
                    break;
                }
                j/=10;
            }
        }
    }
    cout<<f[n-1];
    return 0;
}