# -*- coding: utf-8 -*-

import re
S = raw_input().decode("utf-8")
sp1 = filter(None, re.split(u'ｗ+', S))
sp2 = map(len, filter(None, re.split(u'[^ｗ]+', S)))
if S.startswith(u'ｗ'):
    sp2.pop(0)
if not S.endswith(u'ｗ'):
    sp2.append(0)
m = max(sp2)
for i in xrange(len(sp1)):
    if sp2[i] == m:
        print sp1[i]