#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  t = 1;
  for (int r = 0; r < t; r++) {
    long long n, m, i, x, y, z, sum = 0;
    cin >> n >> m;
    vector<string> v(51);
    char a = 'a', b = 'A';
    for (i = 0; i <= 50; i++) {
      if (b > 'Z') b = 'A';
      v[i].push_back(b);
      if (i >= 26) {
        v[i].push_back(a);
        a++;
      }
      b++;
    }
    x = 0, y = 0;
    vector<string> ans;
    string temp;
    while (y < m - 1) {
      ans.push_back(v[y]);
      y++;
    }
    x = y;
    for (i = 0; i < (n - m + 1); i++, x++) {
      cin >> temp;
      if (temp == "NO") {
        ans.push_back(ans[x - (m - 1)]);
      } else {
        ans.push_back(v[y]);
        y++;
      }
    }
    for (i = 0; i < n; i++) cout << ans[i] << " ";
    cout << "\n";
  }
  return 0;
}
