N=int(input())

def each_digits(n, base=10):
    # 各桁の数字を得る
    digits = []
    a = 1
    while n >= a:
        digits.append(n // a % base)
        a *= base
    return digits[::-1]
n = each_digits(N)
l = len(n)
for i in range(l-1):
    ma = max(n[i+1:])
    if ma>n[i]:
        for j in range(l):
            if n[l-1-j] == ma:
                n[i],n[l-1-j] = n[l-1-j],n[i]
            answer = 0
            for a in n:
                answer *= 10
                answer += a
            print(answer)
            exit()