X = list(map(int, input()))
X.sort()

ans = [X.pop(0)]
while len(X):
    x = X.pop(0)
    if ans[-1] != x:
        ans += [x, ans.pop(0)]
        ans += X
        if ans[-1] != 0:
            print(''.join(map(str, reversed(ans))))
            break
else:
    print(-1)