//line 1 "answer.cpp"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;

const vector<int> ns = {1, 2, 5, 10, 19, 36, 69, 134, 263, 520, 1033, 2058, 4107, 8204, 16397, 32782, 65551, 131088, 262161};
const vector<vector<int>> primitive_polynomials = {
    {},
    {1},
    {1, 2},
    {1, 3},
    {3, 4},
    {3, 5},
    {5, 6},
    {6, 7},
    {4, 5, 6, 8},
    {5, 9},
    {7, 10},
    {9, 11},
    {4, 10, 11, 12},
    {8, 11, 12, 13},
    {2, 12, 13, 14},
    {14, 15},
    {11, 13, 14, 16},
    {14, 17},
    {11, 18},
};
vector<pair<int, int>> lfsr(ll d) {
    vector<int> p = primitive_polynomials[d];
    ll x = (1 << d) - 1;
    vector<int> r;
    while (r.size() == 0 || r[0] != x) {
        r.push_back(x);
        x <<= 1;
        for (auto k : p) if ((x >> k) & 1) x ^= 1;
        if ((x >> d) & 1) x ^= (1 << d);
    }
    r.insert(find(r.begin(), r.end(), (1 << (d-1))) + 1, 0);
    vector<pair<int, int>> result(1 << d);
    for (size_t i=0; i < (1 << d); ++i) { result[r[i]] = {0, r[(i+1) % (r.size())]}; }
    return result;
}

int solve(int n) {
    if (n == 1) {cout << "a" << endl; return 0;}
    int d = (upper_bound(ns.begin(), ns.end(), n) - ns.begin()) - 1;
    vector<vector<pair<int, int>>> c(2);
    c[0] = lfsr(d);
    c[1] = vector<pair<int, int>>(1 << d, {-1, -1});
    int l = ns[d];
    int s = 0;
    unordered_set<int> r;
    for (int x=0; x < (1 << d); ++x) r.insert(x);
    while (l < n) {
        int x = *r.begin();
        while (c[1][x].first == -1) {
            r.erase(x);
            l += 1;
            c[1][x] = {1, c[0][x].second ^ 1};
            x = c[1][x].second;
        }
        s = c[0][x].second;
        swap(c[0][x], c[1][x]);
    }
    pair<int, int> pos = {0, s};
    string ans;
    for (int i=d-1; i >= 0; i--) ans += ((pos.second >> i) & 1) ? 'a' : 'b';
    while (ans.size() < n) {
        auto [t, x] = pos;
        auto [tn, xn] = c[t][x];
        ans += (xn & 1) ? 'a' : 'b';
        pos = {tn, xn};
    }
    cout << ans << endl;
    return 0;
}
int main() {
    int t; cin >> t;
    while (t--) {
        int n; cin >> n;
        solve(n);
    }
}