N = [i for i in input()]

n = N.copy()

n.sort()

n.reverse()


for i in range(len(N)):
    
    if N[i] != n[i]:
        
        for j in range(len(N) - 1, i, -1):
            
            if N[j] == n[i]:
                
                N[i], N[j] = N[j], N[i]
                
                break
        
        break
    
print(''.join(N))