S = input()
ans = 1000
for l in range(len(S)):
    if S[l] != "c":
        continue
    for r in range(l, len(S)):
        if S[r] != "w":
            continue
        if S[l:r+1].count("w")==2:
            ans = min(ans, r-l+1)
            break
if ans == 1000:
    print(-1)
else:
    print(ans)