X = int(input())

L = []
for i in range(len(str(X))):
    L.append(str(X)[i])
L.sort(reverse=True)
if L[0] == L[-1]:
    print(-1)
else:
    for i in range(len(L)-1, 0, -1):
        if L[i] != L[i-1]:
            t = L[i]
            L[i] = L[i-1]
            L[i-1] = t
            break
    if L[0] != "0":
        print("".join(L))
    else:
        print(-1)