#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n, a, b;
    string s = "";
    cin >> n >> a >> b;
    s += 'a';
    for (int i = 1; i < b; i++) {
      s += s[i - 1] + 1;
    }
    string s2 = s;
    for (int i = 0; i < n / b - 1; i++) {
      s += s2;
    }
    for (int i = 0; i < n % b; i++) {
      s += s[i];
    }
    cout << s << endl;
  }
}
