1415.cpp

/**
 *    author:   vulkan
 *    created:  02.08.2021 06:19:12 PM
**/
#include <bits/stdc++.h>

using namespace std;

string _getHappyString(int n, int &k, string curr) {
    if (n == 0) {
        k--;
        if (k == 0) {
            return curr;
        } else {
            return "";
        }
    }

    int sz = curr.size();
    char last = (sz > 0) ? curr[sz - 1] : ' ';

    string ans = "";
    if (last != 'a') {
        ans = _getHappyString(n - 1, k, curr + "a");
    }
    if (ans != "") {
        return ans;
    }

    if (last != 'b') {
        ans = _getHappyString(n - 1, k, curr + "b");
    }
    if (ans != "") {
        return ans;
    }

    if (last != 'c') {
        ans = _getHappyString(n - 1, k, curr + "c");
    }
    return ans;
}


string getHappyString(int n, int k) {
    return _getHappyString(n, k, "");
}

int main(int argc, char const *argv[]) {
    int n, k;
    cin >> n >> k;
    cout << getHappyString(n, k);

    return 0;
}