s = input()

cww = float('inf')

for i in range(len(s)):
    for j in range(i+1, len(s)):
        for k in range(j+1, len(s)):
            if s[i] == "c" and s[j] == "w" and s[k] == "w":
                cww = min(cww, j - i + 1)
            
if cww == float('inf'):
    print(-1)
else:
    print(cww)