#include <bits/stdc++.h>
using namespace std;
long long pwr(long long base, long long p, long long mod = (1000000007LL)) {
  long long ans = 1;
  while (p) {
    if (p & 1) ans = (ans * base) % mod;
    base = (base * base) % mod;
    p /= 2;
  }
  return ans;
}
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long nCr(long long n, long long r) {
  long long C[r + 1];
  memset(C, 0, sizeof(C));
  C[0] = 1;
  for (long long i = 1; i <= n; i++)
    for (long long j = min(i, r); j > 0; j--) C[j] = C[j] + C[j - 1];
  return C[r];
}
bool isPrime(long long n) {
  if (n <= 1) return false;
  if (n == 2) return true;
  if (n % 2 == 0) return false;
  long long m = sqrt(n);
  for (long long i = 3; i <= m; i += 2)
    if (n % i == 0) return false;
  return true;
}
long long M(long long a) { return (a % (1000000007LL)); }
bool isPowerOfTwo(long long x) { return x && (!(x & (x - 1))); }
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(0);
  int n, k;
  cin >> n >> k;
  vector<bool> same_name(n - k + 1);
  int index = 0;
  string s;
  while (index < n - k + 1) {
    cin >> s;
    if (s == "YES") same_name[index] = true;
    index++;
  }
  vector<int> ans(n);
  vector<string> strings(51, "");
  for (long long i = 0; i < (long long)(51); ++i) {
    if (i < 26) {
      strings[i] += (char)(i + 'A');
    } else {
      strings[i] += (char)(i - 26 + 'A');
      strings[i] += (char)(i - 26 + 'a');
    }
  }
  int counter = k;
  if (same_name[0])
    for (long long i = 0; i < (long long)(k); ++i) ans[i] = i;
  else {
    for (long long i = 0; i < (long long)(k - 1); ++i) ans[i] = i;
    ans[k - 1] = ans[0];
    counter--;
  }
  for (int i = 1; i < n - k + 1; i++) {
    if (same_name[i])
      ans[k + i - 1] = counter++;
    else
      ans[k + i - 1] = ans[i];
  }
  for (long long i = 0; i < (long long)(n); ++i) cout << strings[ans[i]] << " ";
  return 0;
}
