import sys
dump = lambda *x : print(*x, file = sys.stderr)

# cawwcww で 4 と返してしまう．
def WA():
    import re

    s = input()
    m = re.search(r'.*c.*w.*w.*?', s)
    dump(m)

    if m is None:
        return(-1)
    else:
        return(len(m.group(0)))


s = input()
n = len(s)

res = 114514

for i in range(n):
    if s[i] != 'c':
        continue

    cnt = 0
    for j in range(i+1,n):
        if s[j] == 'w':
            cnt += 1
        
        if cnt == 2:
            res = min(res, j - i + 1)
            break

if res == 114514:
    res = -1
    
print(res)