#define _CRT_SECURE_NO_WARNINGS
#pragma comment(linker, "/STACK:256000000")
//#include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <set>
#include <string>
#include <algorithm>
#include <queue>
#include <cstdio>
#include <fstream>
#include <unordered_map>
#include <map>
#include <iterator>
#include <iomanip>
#include <stack>
#include <math.h>
#include <bitset>
#include <unordered_set>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef unsigned long long ull;
typedef pair<ll, ll> pll;

#define TASK "queuemin2"
#define X first
#define Y second
#define mp make_pair
#define inb push_back
#define INF 2e9
#define LINF 9e18
#define eps 1e-6
#define y1 dfsdfsd

int n, k;
string s[55];
pii ans[55];

int main()
{
#ifdef _DEBUG
	freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#else
	//freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
	//freopen(TASK".in", "r", stdin), freopen(TASK".out", "w", stdout);
#endif
	cin >> n >> k;
	for (int i = 0; i < n - k + 1; ++i) cin >> s[i];
	vector<pii> b;
	for (int i = 0; i < 26; ++i)
		for (int j = 0; j < 26; ++j)
			b.inb(mp(i, j));
	int l = 0;
	for (int i = 0; i < k - 1; ++i)
		ans[i] = b[l], ++l;
	int r = 0;
	for (int i = 0; i < n - k + 1; ++i)
	{
		if (s[i] == "NO")
			ans[i + k - 1] = ans[r];
		else
			ans[i + k - 1] = b[l], ++l;
		++r;
	}
	for (int i = 0; i < n; ++i)
		cout << (char)('A' + ans[i].X) << (char)('a' + ans[i].Y) << ' ';
}