S = input().strip()

ans = float('inf')

for n in [n for n, i in enumerate(S) if i == 'c']:
  #print(n)
  lst = [m for m, j in enumerate(S) if j == 'w' and m > n][:2]
  #print(n, lst)
  if len(lst) < 2:
    continue
  
  ans = min(ans, lst[1] - n + 1)

print([ans, -1][ans == float('inf')])