s = input().lstrip('ｗ')
sub = s[0]
lst = []
for i in range(1, len(s)):
    if (s[i-1] == 'ｗ') ^ (s[i] == 'ｗ'):
        lst.append(sub)
        sub = s[i]
    else :
        sub += s[i]
lst.append(sub)

ans = []
max = 0
for i in range(len(lst) // 2):
    length = len(lst[i * 2 + 1])
    if length == max:
        ans.append(lst[i * 2])
    elif length > max:
        max = length
        ans = [lst[i * 2]]

for ss in ans:
    print(ss)