s=input()
inf=float("inf")
v=inf
n=len(s)
for i in range(n):
  if s[i]!="c":continue
  for j in range(i+1,n):
    if s[j]!="w":continue
    for k in range(j+1,n):
      if s[k]!="w":continue
      v=min(v,k-i+1)
print(v if v!=inf else -1)