#include <bits/stdc++.h>
using namespace std;
void printVec(vector<long long>& v) {
  for (auto e : v) cout << e << " ";
  cout << endl;
}
int main() {
  map<int, string> names;
  names[1] = "A";
  names[2] = "B";
  names[3] = "C";
  names[4] = "D";
  names[5] = "E";
  names[6] = "F";
  names[7] = "G";
  names[8] = "H";
  names[9] = "I";
  names[10] = "J";
  names[11] = "K";
  names[12] = "L";
  names[13] = "M";
  names[14] = "N";
  names[15] = "O";
  names[16] = "P";
  names[17] = "Q";
  names[18] = "R";
  names[19] = "S";
  names[20] = "T";
  names[21] = "U";
  names[22] = "V";
  names[23] = "W";
  names[24] = "X";
  names[25] = "Y";
  names[26] = "Z";
  names[27] = "Aa";
  names[28] = "Ab";
  names[29] = "Ac";
  names[30] = "Ad";
  names[31] = "Ae";
  names[32] = "Af";
  names[33] = "Ag";
  names[34] = "Ah";
  names[35] = "Ai";
  names[36] = "Aj";
  names[37] = "Ak";
  names[38] = "Al";
  names[39] = "Am";
  names[40] = "An";
  names[41] = "Ao";
  names[42] = "Ap";
  names[43] = "Aq";
  names[44] = "Ar";
  names[45] = "As";
  names[46] = "At";
  names[47] = "Au";
  names[48] = "Av";
  names[49] = "Aw";
  names[50] = "Ax";
  names[51] = "Ay";
  names[52] = "Az";
  int N, K;
  cin >> N >> K;
  int cantcons = N - K + 1;
  vector<long long> cons(cantcons, 0);
  for (int i = 0; i < (int)(cantcons); i++) {
    string c;
    cin >> c;
    if (c == "NO")
      cons[i] = 0;
    else if (c == "YES")
      cons[i] = 1;
  }
  int firstYes = -1;
  vector<long long> namesNum(N, 0);
  for (int i = 0; i < (int)(cantcons); i++)
    if (cons[i]) {
      firstYes = i;
      break;
    }
  if (firstYes != -1) {
    int lastYes = 1;
    for (int i = (firstYes); i < (int)(firstYes + K); i++)
      namesNum[i] = lastYes++;
    for (int i = (firstYes + 1); i < (int)(cantcons); i++) {
      if (cons[i]) {
        namesNum[i + K - 1] = lastYes++;
      } else {
        namesNum[i + K - 1] = namesNum[i];
      }
    }
    for (int i = 0; i < (int)(cantcons); i++) {
      if (!namesNum[i]) namesNum[i] = 1;
    }
  } else {
    namesNum = vector<long long>(N, 1);
  }
  for (auto s : namesNum) {
    cout << names[s] << " ";
  }
  cout << endl;
  return 0;
}
