x=int(input())
q=str(x)
b=[]
for i in range(len(q)):
    b.append(q[i])
b.sort(reverse=True)

t=str()
for i in range(len(q)):
    t+=str(b[i])

t=t[::-1]
ans=str()
cnt=0
cv=0
for i in range(0,len(t)-1):
    if t[i]!=t[i+1] and cnt==0 :
        cnt+=1
        cv=i

for j in range(0,len(t)):
    if j==cv:
        ans+=t[j+1]
        ans+=t[j]
    elif  j==cv+1:
         continue
    else:
        ans+=t[j]



ans=ans[::-1]
if ans==ans[::-1]:
    print(-1)
    exit()
if ans[0]=="0":
    print(-1)
    exit()

print(ans)