#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
 
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define FFOR(i,a,b) for(int i=(a);i<=(b);i++)
#define REP(i,b) FOR(i,0,b)
#define RREP(i,b) FFOR(i,1,b)
#define PB push_back
#define F first
#define S second
#define BE(c) c.begin(),c.end()
using namespace std;
typedef long long LL;
typedef LL ut;
typedef long double ld;
typedef pair<ut,ut> pr;
typedef vector<pr> Vpr;
typedef vector<ut> VI;
typedef pair<ut,pr> ppr;
typedef priority_queue<pr,Vpr, greater<pr> > PQ;
const int SIZE=5+3*1e+4;
const ut INF=1<<30;
const ld eps=1e-6;
const LL p=7+1e+9;

int main(){
	int n, m;
	
	while(cin >> n >> m && (n || m)){
		char c;
		int state[102] = {0};
		state[0] = state[n + 1] = -1;
		REP(i,m){
			cin >> c;
			if(c == 'A'){
				RREP(j,n){
					if(state[j] == 0){
						state[j] = 1;
						break;
					}
				}
			}
			else if(c == 'B'){
				bool ok = false;
				for(int j = n; j > 0; --j){
					if(state[j] == 0 && state[j + 1] != 1 && state[j - 1] != 1){
						state[j] = 2;
						ok = true;
						break;
					}
				}
				if(!ok){
					RREP(j,n){
						if(state[j] == 0){
							state[j] = 2;
							break;
						}
					}
				}
			}
			else if(c == 'C'){
				if(i){
					RREP(j,n){
						if(state[j] != 0){
							if(state[j + 1] == 0){
								state[j + 1] = 3;
								break;
							}
							else if(state[j - 1] == 0){
								state[j - 1] = 3;
								break;
							}
						}
					}
				}
				else{
					if(n % 2){
						state[(n + 1) / 2] = 3;
					}
					else{
						state[n / 2 + 1] = 3;
					}
				}
			}
			else{
				if(i){
					int left = 500, right, tmp;
					RREP(j,n){
						if(state[j] != 0){
							right = j;
							break;
						}
					}
					int maxium = 0, pos = 0;
					RREP(j,n){
						if(state[j] == 0){
							int t = min(left, right);
							if(maxium < t){
								maxium = t;
								pos = j;
							}
						}
						if(right <= j){
							left = right;
							FFOR(k,j + 1,n){
								if(state[k] != 0){
									right = k;
								}
							}
						}
					}
					state[pos] = 4;
				}
				else{
					state[1] = 4;
				}
			}
		}
		RREP(i,n){
			if(state[i] == 0)
				cout << "#";
			else if(state[i] == 1)
				cout << "A";
			else if(state[i] == 2)
				cout << "B";
			else if(state[i] == 3)
				cout << "C";
			else if(state[i] == 4)
				cout << "D";
		}
		cout << endl;
	}
}