import string

datas = raw_input().split(' ')

f = []
f.append('{}:a'.format(datas[0]))
f.append('{}:b'.format(datas[1]))
f.append('{}:c'.format(datas[2]))

x = []
for data in datas:
	x.append(data)

def find(x):
	for ff in f:
		temp = ff.split(':')
		if int(temp[0]) == x:
			return temp[1]

a, b, c = sorted(map(int, x))
print find(a) if (b-a) < (c-b) else find(c)