540 B | 540 chars
import sys
from math import sqrt, pi, sin, factorial
inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = " " : [*map(int,inp().split(x))]
mfi = lambda x = " " : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def solve():
l = input().split()
for i in range(4):
for j in range(3):
if int(l[j] + l[j + 1]) <= int(l[j + 1] + l[j]):
l[j], l[j+1] = l[j+1], l[j]
print(*l, sep="")
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()