// https://qoj.ac/submission/74195

#include <cstdio>
#include <iostream>
using namespace std;

const int o = 1e6;
int n, K, pth[o], cnt, nxt[o];
bool vis[o];
int solve() {
    auto dfs = [&](auto &&self, int nw) -> void {
        if (vis[nw]) return;
        vis[nw] = 1;
        self(self, nw * 2 % (1 << K));
        self(self, (nw * 2 + 1) % (1 << K));
        pth[++cnt] = nw;
    };

    scanf("%d", &n);
    for (int i = 0; i <= n; i++) {
        pth[i] = 0;
        vis[i] = 0;
        nxt[i] = 0;
    }
    cnt = 0;

    if (n == 1) {
        putchar(97);
        return 0;
    }
    for (; (1 << K) + K - 1 <= n; ++K);
    --K;
    dfs(dfs, 0);
    for (int i = 1, j = cnt; i < j; swap(pth[i++], pth[j--]));
    if (n == (1 << K) + K - 1) {
        for (int i = 1; i < K; ++i) putchar(97);
        for (int i = 1; i <= cnt; ++i) putchar(97 + pth[i] % 2);
        return 0;
    }
    for (int i = 0; i < (1 << (K + 1)); ++i) vis[i] = 0, nxt[i] = -1;
    for (int i = 1; i <= cnt; ++i) vis[pth[i] = (pth[i] << 1) | (pth[i + 1] & 1)] = 1;
    for (int i = 1; i <= cnt; ++i) nxt[pth[i]] = pth[i % cnt + 1];
    for (int i = 0; i < (1 << (K + 1)); ++i)
        if (nxt[i] < 0) nxt[i] = nxt[i ^ (1 << K)] ^ 1;
    for (int i = 0, t; i < (1 << (K + 1)); ++i)
        if (!vis[i]) {
            for (t = i; !vis[t]; t = nxt[t]) vis[t] = 1, ++cnt;
            swap(nxt[i], nxt[i ^ (1 << K)]);
            if (cnt + K >= n) {
                for (int j = K; j + 1; --j) putchar(97 + ((nxt[i] >> j) & 1));
                for (int j = K + 2, t = nxt[nxt[i]]; j <= n; ++j, t = nxt[t]) putchar(97 + (t & 1));
                break;
            }
        }
    return 0;
}
int main() {
    int t;
    cin >> t;
    while (t--) {
        solve();
        cout << endl;
    }
    return 0;
}