s = input()

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

if len(l) == 0:
    print(-1)
else:
    print(min(l))