#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <cstring>

#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
using namespace std;

typedef pair<int, int> PII;
typedef long long ll;

//#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
#define FOR2(i,a,b) for(int i = (a); i > (b); --i)
#define FOR(i,b) for(int i = 0; i < (b); ++i)
#define FORTO(i,a,b) for(int i = (a); i <= (b); ++i)
#define FORD(i,b) for(int i = (b)-1; i >= 0; --i)
#define FOREACH(it,a) for(typeof((a).begin()) it = (a).begin(); it != (a).end(); ++it)

#define $(x) int((x).size())

#define MAXN 60000

int Min, Max;

int T[MAXN];

int main()
{
	int N;
	while (true) {
		scanf("%d", &N);
		if (!N) return 0;
		FOR(i,N) {
			scanf("%d", &T[i]);
		}
		sort(T,T+N);
		printf("%d-A", T[0]);
		if (N > 1) {
			printf(" %d-B", T[N-1]);
			bool A = true;
			for (int i = N-2; i >= 1; i--) {
				printf(" %d-%c", T[i], A ? 'A' : 'B');
				A = !A;
			}
		}
		printf("\n");
	}
	return 0;
}