#include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       int n, k, x;       cin >> n >> k;       char s;       string str;       int p = n / k, q = n % k;       for (int i = 0; i < k; ++i) {         x = i + 97;         s = x;         if (i == k - 1) p = p + q;         for (int j = 0; j < p; ++j) str += s;       }       cout << str << endl;     }   }   