import re
import itertools

def main():
    s = ''.join(itertools.dropwhile(lambda x: x == 'ｗ', input()))
    pos = 0
    xs = []
    max_w = 0
    for m in re.finditer('ｗ+', s):
        w = m.end() - m.start()
        x = s[pos:m.start()]
        if max_w < w:
            max_w = w
            xs = [x]
        elif max_w == w:
            xs.append(x)
        pos = m.end()
    for x in xs:
        print(x)

if __name__ == "__main__":
    main()