N = int(input())

S = str(N)
L = len(S)
s = list(S)
a = [int(v) for v in S]
a.sort(reverse=True)
idx = 0
for i in range(L):
    if int(S[i]) != a[i]:
        idx = i
        break
for j in range(L-1, -1, -1):
    if a[idx] == int(S[j]):
        s[idx], s[j] = s[j], s[idx]
        break
ans = ''.join(s)
print(int(ans))