#include <iostream>

using namespace std;

int k, n;

string a[100];
string f[100];

int main(){
	cin >> n >> k;
	for (int i = 1; i <= n-k+1; i++){
		cin >> a[i]; 
	}
	for (int i = 1; i <= 26; i++){
		f[i]="A";
		f[i+26]="B";
	}
	for (int i = 1; i <= 26; i++){
		f[i]+=(char)i+96;
		f[i+26]+=(char)i+96;
	}
	for (int i = 1; i <= n-k+1; i++){
		if (a[i]=="NO"){
			f[i+k-1] = f[i];
		}
	}
	for (int i = 1; i <= n; i++){
		cout << f[i] << " ";
	}
	return 0;
}