X=str(input())
x=[]
y=[]
cnt=0
for i in range(len(X)):
    x.append(X[i])
x.sort(reverse=True)

for i in range(len(x)-2,0,-1):
    if x[i]!=x[i+1] and x[0]!="0":
        x[i],x[i+1]=x[i+1],x[i]
        print("".join(x))
        cnt+=1
        break
if cnt == 0:
    print(-1)