#include<cstdio>
#include<iostream>
using namespace std;
const int o=1e6;
int n,K,pth[o],cnt,nxt[o];bool vis[o];
void dfs(int nw){
	if(vis[nw]) return;
	vis[nw]=1;dfs(nw*2%(1<<K));dfs((nw*2+1)%(1<<K));pth[++cnt]=nw;
}

void solve() {
    scanf("%d",&n);
	if(n==1){putchar(48);return;}
	for(;(1<<K)+K-1<=n;++K);
	--K;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);
		cout << '\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[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));
			cout << '\n';
			break;
		}
	}
}

int main(){
    int t;
    scanf("%d", &t);
    
    while (t--) solve();
	
	return 0;
}