tj-8

#include <bits/stdc++.h>
using namespace std;
long long conver(long long k) {
    vector<int> d;
    while (k > 0) {
        d.push_back(k % 5);
        k /= 5;
    }
    reverse(d.begin(), d.end());
    long long s = 0;
    for (int de : d) {
        s = s * 10 + de * 2;
    }

    return s;
}

int main() {
    long long k;
    cin >> k;
    cout << conver(k - 1) << endl; 
    return 0;
}

5进制