n = input()

x,y,z = [0,0,0]

for i in range(len(n)):
    if n[i] == "c":
        x = i
    elif n[i] == "w":
        if y == 0:
            y = i
        elif z == 0:
            z = i

if z-x+1<0:
    print(-1)
    

else:
    print(z-x+1)