S = input()

ans = float("INF")
for i in range(len(S)):
    start = end = 0
    flg = 0
    if S[i] == "c":
        start = i
        flg += 1
        for j in range(i+1,len(S)):
            if flg == 1 and S[j] == "w":
                flg += 1
            elif flg == 2 and S[j] == "w":
                end = j
                ans = min(ans,end-start+1)
                break

if ans != float("INF"):
    print(ans)
else:
    print(-1)