s = str(input())

a = -1
l = []
for i in s:
    for n, j in enumerate(reversed(l)):
        j.append(i)
        if i == 'w':
            if j.count('w') == 2:
                if len(j) < a or a==-1:
                    a = len(j)
                l.pop(n)
    if i == 'c':
        l.append([i])
print(a)