#include<bits/stdc++.h>
using namespace std;
#define int long long int
#define pb push_back
#define io ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)

void solve()
{
  int n,k,i;
  string s="";
  cin>>n>>k;
  for(i=0;i<k;i++)
  s+="a";


  for(i;i<n;i++)
  {
    if(s[s.size()-1]=='a')
    s+="b";
    else if(s[s.size()-1]=='b')
    s+="c";
    else if(s[s.size()-1]=='c')
    s+="a";
  }
  cout<<s<<endl;


}

int32_t main()
{
  io;
  int t;
  t=1;
  cin>>t;
  while(t--)
  {
    solve();
  }
  return 0;
}
