#include <bits/stdc++.h>
using namespace std;
int main() {
  char letters[] = "abcdefghijklmnopqrstuvwxyz";
  string s;
  int n, k, r;
  cin >> n >> k;
  for (int i = 0; i < k; i++) {
    r = rand() % 26;
    while (letters[r] == '$') {
      r = rand() % 26;
    }
    cout << letters[r];
    s += letters[r];
    letters[r] = '$';
  }
  int len = n - k, c = 0;
  for (int i = 0; i < len; i++) {
    if (i == s.size()) {
      len -= (s.size());
      i = 0;
    }
    cout << s[i];
  }
  return 0;
}
