S = list(input())

start=[]
for i in range(len(S)):
    if S[i]=="c":
        start.append(i)

ans=101
for j in start:
    cnt=0
    for k in range(j+1,len(S)):
        if S[k]=="w":
            if cnt==0:
                cnt+=1
            elif cnt==1:
                ans=min(ans,k+1-j)

if ans==101:
    print(-1)
else:
    print(ans)