N = [int(x) for x in input()]

def f():
    global N
    for j in range(len(N)):
        s = N[j]
        for i in range(len(N)-1,j,-1):
            if s<N[i]:
                N[j]=N[i]
                N[i]=s
                return
f()
print(''.join(map(str,N)))