#include <iostream>
 
using namespace std;
 
 
int main() {
 
 
    int n,k;
    int j = 0;
    string pass = "";
 
    char pick = rand()%25+65;
    char at;
 
 
    cin >> n >> k;
 
 
    for (int i = 1; i<=n; i++) {
 
 
        if (i<=k) {
            at = (char)(pick+j);
            pass += at;
        }
        else {
           pass+=at;
        }
 
 
        j++;
 
    }
 
    cout << pass << endl;
 
 
    return 0;
 
 
 
}