#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define PI acos(-1)
#define LSB(i) ((i) & -(i))
#define ll long long
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define fi first
#define sc second
#define th third
#define fo fourth
#define pii pair<int,int>
#define pll pair<ll,ll>
#define ldb double
#define INF 1e15
#define MOD 1000000007
#define endl "\n"

#define all(data)       data.begin(),data.end()
#define TYPEMAX(type)   std::numeric_limits<type>::max()
#define TYPEMIN(type)   std::numeric_limits<type>::min()
#define MAXN 1000007
ll p[MAXN],nxt[MAXN],cnt,k;
bool vis[MAXN];
void DFS(ll i)
{
	vis[i]=true;
	if(!vis[i*2%(1<<k)]) DFS(i*2%(1<<k));
	if(!vis[(i*2+1)%(1<<k)]) DFS((i*2+1)%(1<<k));
	p[++cnt]=i;
}

void solve() {
    ll n; cin>>n;
    k = 0;
	while((1<<k)+k<=n+1) k++;
	k--; DFS(0);
	ll ii=1,jj=cnt;
	while(ii<jj) swap(p[ii++],p[jj--]);
	string ans;
	if(n==(1<<k)+k-1)
    {
		for(int i=1;i<k;i++) ans += 'a';
		for(int i=1;i<=cnt;i++) ans += ('a'+(p[i]&1));
		cout << ans << '\n';
		return;
	}
	for(int i=0;i<(1<<(k+1));i++) {vis[i]=0; nxt[i]=-1;}
	for(int i=1;i<=cnt;i++)
    {
        vis[p[i]=(p[i]<<1)|(p[i+1]&1)]=true;
    }
	for(int i=1;i<=cnt;i++) nxt[p[i]]=p[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;i<(1<<(k+1));i++)
    {
        if(!vis[i])
        {
            ii=i;
            while(!vis[ii]) {cnt++; vis[ii]=true; ii=nxt[ii];}
            swap(nxt[i],nxt[i^(1<<k)]);
            if(cnt+k>=n)
            {
                for(int j=k;j+1;j--) ans += ('a'+((nxt[i]>>j)&1));
                jj=nxt[nxt[i]];
                for(int j=k+2;j<=n;j++) { ans += ('a'+(jj&1)); jj=nxt[jj];}
                cout << ans << '\n';
                break;
            }
        }
	}
}

int main()
{
    ios::sync_with_stdio(false); cin.tie(0);
    int t;
    cin >> t;
    
    while (t--) solve();
	
	return 0;
}