#include <bits/stdc++.h>
using namespace std;
string getName(int x) {
  string res = "";
  if (x < 27) {
    res += char(x + 96);
    return "A" + res;
  } else {
    res += char(x - 26 + 96);
    return "B" + res;
  }
}
int n, k, a[101];
string s[101];
bool was[101];
int main() {
  cin >> n >> k;
  for (int i = 0; i < n - k + 1; ++i) cin >> s[i];
  for (int i = 0; i < k - 1; ++i) {
    a[i] = i + 1;
    was[i + 1] = true;
  }
  for (int i = 0; i < n - k + 1; ++i) {
    if (s[i] == "NO")
      a[k + i - 1] = a[i];
    else {
      if (i > 0) {
        bool ok = false;
        for (int j = i; j < i + k - 1; ++j)
          if (a[j] == a[i - 1]) ok = true;
        if (!ok) was[a[i - 1]] = false;
      }
      for (int j = 1; j < 51; ++j) {
        if (!was[j]) {
          was[j] = true;
          a[k + i - 1] = j;
          break;
        }
      }
    }
  }
  for (int i = 0; i < n; ++i) cout << getName(a[i]) << " ";
  return 0;
}
