#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int i, j, k, rest, n;
  char ch, ch1;
  cin >> n >> k;
  rest = n - k;
  ch = 'a';
  for (i = 0; i < k; i++) {
    cout << ch;
    ch += 1;
  }
  ch1 = 'a';
  for (i = 0, j = 1; i < rest; i++, j++) {
    cout << ch1;
    ch1 += 1;
    if (j == k) {
      ch1 = 'a';
      j = 0;
    }
  }
  cout << endl;
  return 0;
}
