# Here your code !

s=gets

tmp=s.count('ｗ')

if tmp==0||tmp==s.size then
    print "\n"
    exit(0)
end

while s.size!=0&&s[0]=='ｗ' do
    s=s[1,s.size-1]
end

while s.size!=0&&s[s.size-1]!='ｗ' do
    s=s[0,s.size-1]
end

ma=0
lis=[]

while s.size!=0 do
    c=0
    while c<s.size&&s[c]!='ｗ' do
        c+=1
    end
    ss=s[0,c]
    s=s[c,s.size-c]
    
    c=0
    while c<s.size&&s[c]=='ｗ' do
        c+=1
    end
    s=s[c,s.size-c]
    if ma<c then
        lis=[ss]
        ma=c
    elsif ma==c then
        lis.push(ss)
    end
end

for e in lis
    print e+"\n"
end