s = input()
if s.count('c') == 0 or s.count('w') < 2:
    print(-1)

w1 = s.find('w')
wn = s.rfind('w')
w = 0
ww = 0
cww = 101

for c in range(len(s)):
    if s[c] == 'c' and s[c:].count('w') >= 2:
        w = s[c:].index('w') + c
        ww = s[w+1:].index('w') + w + 1
        if cww > ww - c + 1:
            cww = ww - c + 1

if cww == 101:
    print(-1)
else:
    print(cww)