cnt=0;c_check=0;w_check=0;ans=[]
s=input()
for i in range(len(s)):
    for j in range(i,len(s)):
        if s[j]=='c':
            cnt+=1
            c_check=1
        elif s[j]=='w':
            if c_check==0:
                continue
            if w_check==0:
                w_check+=1
                cnt+=1
            else:
                cnt+=1
                w_check=0
                c_check=0
                ans.append(cnt)
                cnt=0
        elif c_check==1:
            cnt+=1
print(min(ans) if ans else -1)