s = input()

if 'c' in s:
    x = s.index('c')
    t = s[x+1:]
    if 'w' in t:
        y = t.index('w')
        u = t[y+1:]
        if 'w' in u:
            z = u.index('w')
            print(x+y+z+3-x)
        else:
            print(-1)
    else:
        print(-1)
else:
    print(-1)