import pickle, random
def isContain(c, x):
	while x > 0:
		d = x % 10
		if d == c:
			return True
		x //= 10
	return False

def dd(x):
	while x > 0:
		d = x % 10
		x //= 10
		if isContain(d, x):
			return False
	return True

def count(a, x):
	b = 0
	for i in a:
		if i == x:
			b += 1
	return b

n = 0
gc = []
g = []
f = open('input.dat', 'rb')
while True:
	try:
		a = pickle.load(f)
		if dd(a):
			g.append(a)
	except EOFError:
		break
f.close()
for i in g:
	gc.append(count(g, i))
for i in g:
	if max(gc) == count(g, i):
		n = i
		break
print(n)