A = [0, 1, 2, 1, 3, 2, 1, 9, 4, 3, 2, 8, 1, 9, 19, 7, 5, 4, 3, 7, 2, 8, 18, 6, 1, 9, 19, 9, 29, 6, 7, 69, 6, 5, 4, 6, 3, 7, 17, 5, 2, 8, 18, 8, 28, 5, 6, 59, 1, 9, 19, 9, 29, 8, 9, 58, 39, 5, 6, 59, 7, 69, 169, 47, 7, 6, 5, 5, 4, 6, 16, 4, 3, 7, 17, 7, 27, 4, 5, 49, 2, 8, 18, 8, 28, 14, 8, 48, 38, 4, 5, 49, 6, 59, 159, 37, 1, 9, 19, 9, 29, 8, 9, 47, 39, 7, 8, 48, 9, 58, 158, 36, 49, 4, 5, 49, 6, 59, 159, 39, 7, 69, 169, 36, 269, 37, 47, 469, 8, 7, 6, 4, 5, 5, 15, 3, 4, 6, 16, 6, 26, 3, 4, 39, 3, 7, 17, 7, 27, 13, 7, 38, 37, 3, 4, 39, 5, 49, 149, 27, 2, 8, 18, 8, 28, 18, 8, 37, 38, 13, 14, 38, 8, 48, 148, 26, 48, 3, 4, 39, 5, 49, 149, 29, 6, 59, 159, 26, 259, 27, 37, 369, 1, 9, 19, 9, 29, 8, 9, 36, 39, 7, 8, 37, 9, 47, 147, 25, 49, 6, 7, 38, 8, 48, 148, 28, 9, 58, 158, 25, 258, 26, 36, 359, 59, 3, 4, 39, 5, 49, 149, 29, 6, 59, 159, 28, 259, 29, 39, 358, 7, 69, 169, 25, 269, 26, 36, 359, 369, 27, 37, 369, 47, 469, 1469, 247, 9, 8, 7, 3, 6, 4, 14, 2, 5, 5, 15, 5, 25, 2, 3, 29, 4, 6, 16, 6, 26, 12, 6, 28, 36, 2, 3, 29, 4, 39, 139, 17, 3, 7, 17, 7, 27, 17, 7, 27, 37, 12, 13, 28, 7, 38, 138, 16, 47, 2, 3, 29, 4, 39, 139, 19, 5, 49, 149, 16, 249, 17, 27, 269, 2, 8, 18, 8, 28, 18, 8, 26, 38, 17, 18, 27, 8, 37, 137, 15, 48, 12, 13, 28, 14, 38, 138, 18, 8, 48, 148, 15, 248, 16, 26, 259, 58, 2, 3, 29, 4, 39, 139, 19, 5, 49, 149, 18, 249, 19, 29, 258, 6, 59, 159, 15, 259, 16, 26, 259, 359, 17, 27, 269, 37, 369, 1369, 147, 1, 9, 19, 9, 29, 8, 9, 25, 39, 7, 8, 26, 9, 36, 136, 14, 49, 6, 7, 27, 8, 37, 137, 17, 9, 47, 147, 14, 247, 15, 25, 249, 59, 5, 6, 28, 7, 38, 138, 18, 8, 48, 148, 48, 248, 18, 28, 248, 9, 58, 158, 14, 258, 15, 25, 249, 358, 16, 26, 259, 36, 359, 1359, 137, 69, 2, 3, 29, 4, 39, 139, 19, 5, 49, 149, 18, 249, 19, 29, 247, 6, 59, 159, 17, 259, 18, 28, 248, 359, 19, 29, 258, 39, 358, 1358, 136, 7, 69, 169, 14, 269, 15, 25, 249, 369, 16, 26, 259, 36, 359, 1359, 139, 469, 17, 27, 269, 37, 369, 1369, 136, 47, 469, 1469, 137, 2469, 147, 247, 2469]

N = int(input());
S = list(map(int, input().split()))
S.sort()
if N%2 == 0:
    cur = 0
    for c in S:
        cur ^= 1<<(c-1)
    print(A[cur])
else:
    n = N//2 + 1
    a = 0
    for i in range(N//2+1):
        a = a*10 + S[i]
    b = 0
    for i in range(N-1, N//2, -1):
        b = b*10 + S[i]
    print(a-b)