#include <bits/stdc++.h>
using namespace std;
#define ll long long



int main()
{

    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t;
    cin >> t;
    int n, k;
    while (t--)
    {
        char a[3] = {'a','b','c'};
        cin >> n >> k; 
        int temp = k; 
        while(k--) {
            cout<<a[0];
        }
        int i = 1;
        n = n - temp;
        //cout << n;
        while(n--) {
            
            if(i == 3){
                i = 0;
            }
            cout<<a[i];
            i++;
        }   
        cout << endl;
    }

    return 0;
}