#include <bits/stdc++.h>
using namespace std;
int const N = 200 * 1000 + 16;
int const M = 1000 * 1000 * 1000 + 7;
int const inf = 1000 * 1000 * 1000;
int n, m, k;
int a[64];
string s[64];
char w[16];
int c[64];
int main() {
  cin.tie(0);
  cin.sync_with_stdio(0);
  for (int i = 0; i < 26; ++i) {
    s[i].assign(1, 'A' + i);
    s[i + 26].assign(1, 'a' + i);
    s[i + 26] = s[i] + s[i + 26];
  }
  cin >> n >> k;
  for (int i = 0; i < k - 1; ++i) {
    c[i] = 1;
    a[i] = i;
  }
  for (int i = k - 1; i < n; ++i) {
    int j = i - (k - 1);
    cin >> w;
    if (w[0] == 'Y') {
      for (int x = 0; x < k; ++x)
        if (not c[x]) {
          c[x]++;
          a[i] = x;
          break;
        }
    } else {
      a[i] = a[j];
      c[a[i]]++;
    }
    c[a[j]]--;
  }
  cout << s[a[0]];
  for (int i = 1; i < n; ++i) cout << " " << s[a[i]];
  cout << endl;
}
