Text = []
A = {}
c = []
S = []
with open ('input.txt') as f:
    for line in f:
        for i in line.split():
            Text.append(i)
            A[i] = Text.count(i)
            c.append(Text.count(i))
for i in A:
    if A[i] == max(c):
        S.append(i)
with open('output.txt', 'w') as F:
    print(min(S), file = F)