#include <iostream>
#include <algorithm>
 
using namespace std;

#define MAX 100

int n,m;
char chair[MAX+2];
  
void A()
{
    for (int i = 1; i <= n; i++) {
	if (chair[i] == '#') {
	    chair[i] = 'A';
	    return;
	}
    }
}
 
void B()
{
    int pos = -1;
    for (int i = 1; i <= n; i++) {
	if (chair[i] == 'A') {
	    pos = i;
	    break;
	}
    }
   
    if (pos == -1) {
	for (int i = n; i > 0; i--) {
	    if (chair[i] == '#') {
		chair[i] = 'B';
		return;
	    } 
	}
    } else {
	for (int i = n; i > 0; i--) {
	    if (chair[i] == '#' && chair[i-1] != 'A' && chair[i+1] != 'A') {
		chair[i] = 'B';
		return;
	    }
	}
  
	for (int i = 1; i <= n; i++) {
	    if (chair[i] == '#') {
		chair[i] = 'B';
		return;
	    }
	}
    }
}
  
void C()
{
    int cnt = count(chair, chair+n, '#');
  
    if (cnt == n) {
	if (n % 2) {
	    chair[(n+1)/2] = 'C';
	} else {
	    chair[n/2+1] = 'C';
	}
    } else {
	for (int i = 1; i <= n; i++) {
	    if (chair[i] != '#' && chair[i+1] == '#' && i != n) {
		chair[i+1] = 'C';
		return;
	    }
	    if (chair[i] != '#' && chair[i-1] == '#' && i != 1) {
		chair[i-1] = 'C';
		return;
	    }
	}
    }
}
  
void D()
{
    int Breadth = 0, pos;
    int cnt = count(chair, chair+n, '#');
 
    if (cnt == n) {
	chair[1] = 'D';
	return;
    } 
 
    for (int i = 1; i <= n; i++) {
	int dist = (1<<29);
	if (chair[i] != '#') continue;
	for (int j = 1; j <= n; j++) {
	    if (chair[j] != '#') {
		dist = min(dist, abs(j-i)+1);
	    }
	}
	if (Breadth < dist) {
	    Breadth = dist;
	    pos = i;
	} 
    }
  
    chair[pos] = 'D';
}
  
int main()
{
    while (cin >> n >> m, n | m) {
	char person;
  
	for (int i = 0; i <= n+1; i++) {
	    chair[i] = '#';
	}
  
	for (int i = 0; i < m; i++) {
	    cin >> person;
       
	    switch (person) {
                case 'A': 
                    A(); 
                    break;
                case 'B': 
                    B(); 
                    break;
                case 'C': 
                    C(); 
                    break;
                case 'D': 
                    D(); 
                    break;
	    }
	}
	for (int i = 1; i <= n; i++) {
	    cout << chair[i];
	}
	cout << endl;
    }
    return 0;
}