#include <bits/stdc++.h>
using namespace std;
int main() {
  char a[51][5];
  int i, j, k, l = 1;
  for (i = 0; i < 51; i++) {
    a[i][0] = 'A';
    a[i][1] = 'b';
  }
  for (i = 0; i < 51; i++) {
    a[i][0] += i / 25;
    a[i][1] += i % 25;
    a[i][2] = '\0';
  }
  int n, m;
  cin >> n >> k;
  char s[n + 1][5];
  for (i = 1; i <= n; i++) s[i][2] = '\0';
  for (i = 1; i <= n - k + 1; i++) {
    char h[5];
    scanf("%s", h);
    if (h[0] == 'N') {
      if (i == 1) {
        for (j = 1; j < k; j++) {
          s[j][0] = a[l][0], s[j][1] = a[l][1];
          l++;
        }
        s[j][0] = a[1][0], s[j][1] = a[1][1];
      } else {
        s[i + k - 1][0] = s[i][0], s[i + k - 1][1] = s[i][1];
      }
    } else {
      if (i == 1) {
        for (j = 1; j <= k; j++) {
          s[j][0] = a[l][0], s[j][1] = a[l][1];
          l++;
        }
      } else {
        s[i + k - 1][0] = a[l][0], s[i + k - 1][1] = a[l++][1];
      }
    }
  }
  for (i = 1; i < n; i++) printf("%s ", s[i]);
  printf("%s\n", s[i]);
}
