#include <bits/stdc++.h>
using namespace std;
const int N = 150001;
vector<int> A[N];
vector<pair<int, int> > re;
int par[N], ed[N], no[N];
int find(int a) {
  if (a == par[a]) return a;
  return par[a] = find(par[a]);
}
void add(int a, int b) {
  a = find(a);
  b = find(b);
  ed[a] += ed[b] + 1;
  no[a] += no[b];
  par[b] = a;
}
string ad(string a) {
  if (a == "Z" || a == "ZZ") {
    a += 'a';
  }
  if (a > "Z")
    a[1] += 1;
  else
    a[0]++;
  return a;
}
int main() {
  int n, m;
  bool V[100];
  scanf(" %d %d", &n, &m);
  vector<string> ans;
  string nm = "A";
  for (int i = 0; i <= n - m; i++) {
    string s;
    cin >> s;
    if (s[0] == 'Y')
      V[i] = 1;
    else
      V[i] = 0;
  }
  int l = 0;
  for (int i = 0; i < m - 1; i++) {
    ans.push_back(nm);
    nm = ad(nm);
  }
  for (int i = 0; i <= n - m; i++) {
    if (V[i]) {
      ans.push_back(nm);
      nm = ad(nm);
    } else
      ans.push_back(ans[ans.size() - m + 1]);
  }
  for (int i = 0; i < ans.size(); i++) {
    cout << ans[i] << " ";
  }
  return 0;
}
