#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <map>
#include <vector>
using namespace std;

char seat[110];
bool is_seat = false;
int n, m;

void A(){
  for(int i = 0 ; i < n ; i++){
    if(seat[i] == '#'){
      seat[i] = 'A';
      is_seat = true;
      return;
    }
  }
}

void B(){
  bool flag = false;
  for(int i = n-1 ; i >= 0 ; i--){
    if(seat[i-1] != 'A' && seat[i] == '#'){
      seat[i] = 'B';
      flag = true;
      is_seat = true;
      return;
    }
  }
  if(!flag){
    for(int i = 0 ; i < n ; i++){
      if(seat[i] == '#'){
	seat[i] = 'B';
	is_seat = true;
	return;
      }
    }
  }
}

void C(){
  if(!is_seat){
    if(n % 2 == 1) seat[(n+1)/2-1] = 'C';
    else seat[n/2+1-1] = 'C';
    is_seat = true;
    return;
  }
  else{
    for(int i = 0 ; i < n ; i++){
      if(seat[i] != '#'){
	if(seat[i+1] == '#'){
	  seat[i+1] = 'C';
	  is_seat = true;
	  return;
	}
	else{
	  if(seat[i-1] == '#'){
	    seat[i-1] = 'C';
	    is_seat = true;
	    return;
	  }
	}
      }
    }
  }
}

void D(){
  bool Must_left = true;
  vector<pair<int, int> > check;
  if(!is_seat){
    is_seat = true;
    seat[0] = 'D';
    return;
  }
  
  for(int i = 0 ; i < n ; i++){
    if(seat[i-1] == '#' && seat[i+1] == '#') Must_left = false;
  }
  for(int i = 0 ; i < n ; i++){
    if(seat[i] == '#'){
      int cnt = 0;
      int len;
      for(int j = i-1 ; seat[j] == '#' || j >= 0; j--) cnt++;
      len = cnt; cnt = 0;
      for(int j = i+1 ; seat[j] == '#' || j < n ; j++) cnt++;
      len = max(len, cnt);
      check.push_back(make_pair(len, i));
    }
  }
  sort(check.begin(), check.end());
  for(int i = 0 ; i < check.size() ; i++){
    if(check[i].first == check[i+1].first) Must_left = true;
  }

  if(Must_left){
    for(int i = 0 ; i < n ; i++){
      if(seat[i] == '#'){
	seat[i] = 'D';
	is_seat = true;
	return;
      }
    }
  }
  else{
    seat[check[0].second] = 'D';
    is_seat = true;
    return;
  }
}

int main(){
  while(cin >> n >> m){
    if(n == 0 && m == 0) break;
    fill(seat, seat+n, '#');
    char p;
    is_seat = false;
    while(m--){
      cin >> p;
      if(p == 'A') A();
      else if(p == 'B') B();
      else if(p == 'C') C();
      else if(p == 'D') D();
      /*for(int i = 0 ; i < n ; i++)cout << seat[i];
      cout << endl;*/
    }
    for(int i = 0 ; i < n ; i++)cout << seat[i];
    cout << endl;
  }
  return 0;
}