s = input()
ans = []

for i in range(len(s)):
    if s[i] == "c":
        if "w" in s[i:]:
            a = s.index("w", i) + 1
            if "w" in s[a:]:
                b = s.index("w", a) + 1
                ans.append(s[i:b])
                
if len(ans) == 0:
    print(-1)
else:
    minn = len(ans[0])
    for i in ans:
        if minn > len(i):
            minn = len(i)
    print(minn)