S=input()
a=l=len(S)
i,j,f=0,1,0
while i<l+1:
    while j<l+1:
        x=S[i:j]
        t=list('cww')
        for y in x:
            if y==t[0]:t.pop(0)
        if t==[]:
            f=1
            i+=1
            a=min(a,len(x))#update
        else:j+=1
    i+=1
if f:print(a)
else:print(-1)