def solve(N, ws, A): accs = set([0]) for w in ws: if w > A: return False accs_ = set(accs) for a in accs: na = w + a if na == A: return True elif na < A: accs_.add(na) accs = accs_ return False def main(): N = int(input()) ws = set(list(map(int, input().split()))) Sum = sum(ws) if Sum % 2 == 0: A = Sum // 2 if solve(N, ws, A): print('possible') else: print('impossible') else: print('impossible') main()