string = input()
c_pos = []
w_pos = []
for i, s in enumerate(string):
    if s == "c":
        c_pos.append(i)
    elif s == "w":
        w_pos.append(i)

ans = 1000

for num in c_pos:
    tmp = 0
    for num2 in w_pos:
        if num < num2:
            tmp += 1
            if tmp == 2:
                ans = min(ans, num2 - num + 1)
if ans == 1000:
    print(-1)
else:
    print(ans)