#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, d;
  scanf("%d%d", &n, &d);
  char a[n];
  for (int i = 0; i < n; i++) {
    if (i < d)
      a[i] = 97 + i;
    else
      a[i] = a[i % d];
  }
  for (int i = 0; i < n; i++) printf("%c", a[i]);
  return 0;
}
