s = raw_input()
find = False
for i in range(len(s)):
    if s[i] == 'c':
        w = 0
        for j in range(i+1,len(s)):
            if s[j] == 'w':
                w += 1
            if w == 2:
                print j-i+1
                find = True
                break
    if find:
        break
if not find:
    print -1