N=list(map(int,list(input())))
#print(N)
x=max(N)
n=min(N)
for i in range(len(N))[::-1]:
    if N[i]==x:
        y=i
        break

for i in range(len(N)):
    if N[i]!=x:
        o=i
        break
else:o=y

if y>o:N[y],N[o]=N[o],N[y]
print(''.join([str(x) for x in N]))