S = input()
a = 101
for i in range(len(S)):
    c = S.find('c',i)    
    if c != -1:
        w1 = S.find('w',c+1)
        if w1 != -1:
            w2 = S.find('w',w1+1) + 1
            if w2 != -1:
                if a > w2:
                    a = w2 - c
if a == 101:
    print(-1)
else:
    print(a)