S=input()
min=101

if S.count("c")<1 or S.count("w")<2:
    print(-1)
else:
    for (i,x) in enumerate(S):
        if x=="c":
            count=0
            l=1

            for y in S[i+1:]:
                l+=1
                if y=="w":
                    count+=1
                    if count==2:
                        break
            if count==2:
                if l<min:
                    min=l
    print(min)