S = input()
c = 0
w = 0
if S.count("c") !=1:
    print(-1)
elif S.count("w") <=1:
    print(-1)
else:
    for i in range(len(S)):
        if S[i] == "c":
            c = i
            break
    for i in range(len(S)):
        if S[i] == "w":
           w += 1
           if w == 2:
               print(i+1-c)