#include<bits/stdc++.h>

#define REP(i,s,n) for(int i=s;i<n;i++)
#define rep(i,n) REP(i,0,n)

using namespace std;

char tmp[200];

int main(){
  int n,m;
  while( cin >> n >> m, n|m ){
    rep(i,n) tmp[i] = '#';
    rep(_,m){
      char c;
      cin >> c;
      if( c == 'A' ){
        rep(i,n) if( tmp[i] == '#' ) {
          tmp[i] = c;
          break;
        }
      } else if( c == 'B' ) {
        bool ok = false;
        for(int i=n-1;i>=0;i--) if( tmp[i] == '#' ) {
          int res = 0;
          if( 0 <= i-1 ) res += (tmp[i-1]=='A');
          if( i+1 < n  ) res += (tmp[i+1]=='A');
          if( res ) continue;
          tmp[i] = c;
          ok = true;
          break;
        }
        if( !ok ) {
          rep(i,n) if( tmp[i] == '#' ) {
            tmp[i] = c;
            break;
          }
        }
      } else if( c == 'C' ) {
        bool failed = false;
        rep(i,n) if(tmp[i]!='#') {
          failed = true;
          break;
        }
        if( !failed ) {
          tmp[n/2] = c;
        } else {
          rep(i,n) if( tmp[i] != '#' ){
            if( i+1 < n && tmp[i+1] == '#' ){
              tmp[i+1] = c;
              break;
            }
            if( 0 <= i-1 && tmp[i-1] == '#' ){
              tmp[i-1] = c;
              break;
            }
          }
        }
      } else {
        bool flag = true;
        rep(i,n) if( tmp[i] != '#' ) {
          flag = false;
          break;
        }
        if( flag ){
          tmp[0] = c;
        } else {
          int pos = -1, maxi = -1;
          rep(i,n)if(tmp[i]=='#'){
            int cost = 0, x = i;          
            while( 0 <= x-1 ) {
              x--;
              if( tmp[x] != '#' ) break;
              cost++;
            }
            if( x == 0 && tmp[x] == '#' ) cost = 200;
            int cost2 = 0;
            x = i;
            while( x+1 < n ){
              x++;
              if( tmp[x] != '#' ) break;
              cost2++;
            }

            if( x == n-1 && tmp[x] == '#' ) cost2 = 200;
            cost = min(cost,cost2);
            if( cost > maxi ){
              maxi = cost;
              pos = i;
            }
          }
          assert( pos != -1 );
          tmp[pos] = c;
        }
      }
    }
    rep(i,n) cout << tmp[i]; cout << endl;
  }
  return 0;
}