S = input()
ans = 101
for i in range(0,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

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