S=input()
stack=''
i=j=0
ans=len(S)

found=0
while i<len(S)+1:
    while j<len(S)+1:
        x=S[i:j]
        if x.count('c')>=1 and x.count('w')>=2 and x.index('c')<x.index('w'):
            found=1
            i+=1
            ans=min(ans,len(x))#update
        else:
            j+=1
    i+=1
if found:print(ans)
else:print(-1)