N7

#include <iostream>
#include <cmath>
#include <vector>
#include <queue>
#include <algorithm>
#include <string>
#include <stack>
#include <set>
#include <map>
#define pii pair <int, int>
#define pb(x) push_back(x)
using namespace std;
using ll = long long;
using ld = long double;
using db = double;
void cv(vector <int> &v) {
    for (auto x : v) cout << x << ' ';
    cout << "\n";
}

void cvl(vector <ll> &v) {
    for (auto x : v) cout << x << ' ';
    cout << "\n";
}


void cvv(vector <vector <int> > &v) {
    for (auto x : v) cv(x);
    cout << "\n";
}

void cvb(vector <bool> v) {
    for (bool x : v) cout << x << ' ';
    cout << "\n";
}

void cvs(vector <string>  v) {
    for (auto a : v) {
        cout << a << "\n";
    }
}

void cvp(vector <pii> a) {
    for (auto p : a) {
        cout << p.first << ' ' << p.second << "\n";
    }
    cout << "\n";
}



int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    vector <char> l = {'a', 'b', 'c', 'd'};
    vector <string> v;
    for (char a: l) for (char b: l) for (char c: l) for (char d: l) {
        string s = "";
        s += a;
        s += b;
        s += c;
        s += d;
        v.pb(s);
    }
    //cvs(v);
    cout << v[249];
}