#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a;
  cin >> n >> a;
  string w;
  w.clear();
  int j = 0, y = 0, s = 1111;
  for (int i = 0; i < n; i++) {
    if (a == 0 && j != 1) {
      j = 0;
      y = s;
    } else if (y == s) {
      y = 0;
      j = 0;
    } else if (a > 0)
      a--;
    s = j + 97;
    char x = (char)s;
    w = w + x;
    j++;
  }
  cout << w << endl;
  return 0;
}
