ans=1000000
s=input()
for i in range(len(s)):
    res=0
    for j in range(i,len(s)):
        if res==2 and s[j]=='w':
            ans=min(ans,j-i+1)
            break
        elif res==1 and s[j]=='w':
            res+=1
        elif res==0 and s[j]=='c':
            res+=1
if ans>1000:
    print(-1)
else:
    print(ans)