S = input()
L = len(S)
import re
cand = []
for i in range(L-1):
    for j in range(i+1, L+1):
        if re.match("c.*w.*w",S[i:j]):
            cand += [j-i]
            break
if cand:
  print(min(cand))
else:
  print(-1)