//----------Bajrang Bali ki jai-------------------
//----------Code submitted by Akash Kumar---------
//----------Toh chaliye shuru karte hain----------
#include<bits/stdc++.h>
typedef long long int ll;
#define jaldi       ios::sync_with_stdio(0); cin.tie(0)
#define testcase    ll t;cin>>t;while(t--)
#define fw(i,a,b)   for(i=a;i<b;i++)
#define fw1(i,a,b)  for(i=a;i<=b;i++)
#define bw(i,a,b)   for(i=a;i>b;i--)
#define bw1(i,a,b)  for(i=a;i>=b;i--)
#define pb          push_back
#define vec         vector<ll>
#define mll         map<ll,ll>
#define F           first
#define S           second
#define lcm(a,b)    (a*b)/(__gcd(a,b))
#define yes         cout<<"YES"<<endl
#define no          cout<<"NO"<<endl
#define prt(x)      cout<<x
#define prts(x)     cout<<x<<" "
#define prtl(x)     cout<<x<<endl
#define prtnl()     cout<<"\n"
#define endl        "\n"

const ll mod = 1000000007; //10^9+7

using namespace std;

void toh_chaliye_shuru_karte_hain()
{
#ifndef ONLINE_JUDGE
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
#endif
}

void code_samapti_ki_ghoshna()
{
#ifndef ONLINE_JUDGE
  cout << "\nTime Elapsed : " << 1.0 * clock() / CLOCKS_PER_SEC << " s\n";
#endif
}

ll power(ll a, ll b, ll modi)
{
  a %= modi;
  ll res = 1 ;
  while (b)
  {
    if (b % 2)
    {
      res = (res * a) % modi ;
    }
    b /= 2 ;
    a = (a * a) % modi ;
  }
  return res ;
}

int main()
{
  toh_chaliye_shuru_karte_hain(); //for input and output
  jaldi; // fast input
  testcase
  {
    int n, k;
    cin >> n >> k;
    string ans = "";
    char ch[3];
    ch[0] = 'a';
    ch[1] = 'b';
    ch[2] = 'c';
    int i, j = 0;
    fw(i, 0, n - k)
    {
      if (j == 2)
      {
        ans += ch[j];
        j = 0;
      }
      else
      {
        ans += ch[j];
        ++j;
      }
    }
    fw(i, 0, k)
    {
      ans += ch[j];
    }
    prtl(ans);
  }
  code_samapti_ki_ghoshna();
  return 0;
}