s = input()

lst = []
for i in range (0, len(s)):
    if s[i] == 'c':
        for j in range (i+1, len(s)):
            if s[j] == 'w':
                for k in range(j+1, len(s)):
                    if s[k] == 'w':
                        lst.append(k-i+1)

if (lst.count > 0):
     print (min(lst))
else :
    print (-1)