n=list(input())
ans=[]
for i in range(1,len(n)):
    if int(n[0])<int(n[i]):
        ans.append([i,int(n[i])])

ans.sort(key=lambda x:-x[1])
p=n.copy()
if len(ans)==0:
    n="".join(n)
    exit(print(n))
n[ans[0][0]],n[0]=p[0],str(ans[0][1])
n="".join(n)