S = input()

ans = 101

for i in range(len(S)-2):
    for j in range(i+2,len(S)):
        if S[i] == 'c' and S[j] == 'w' and S[i:j+1].count('w') == 2:
            ans = min(ans, j-i+1)
        else:
            continue

print(ans if ans != 101 else -1)