Ponto do Meio

#include <bits/stdc++.h>
using namespace std;
#define int long long

int32_t main() {

    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    __int128_t f = 1, v = 4, a = 4;

    while(n--) {
        v = v + a + f;
        f *= 4;
        a = v + f - 1;
    }

    vector<int> ans;

    while(v) {
        ans.push_back(v % 10);
        v /= 10;
    }

    for(int i = (int)ans.size() - 1; i >= 0; i--)
        cout << ans[i];
    cout << endl;

    return 0;
}