24

s = open('24_23762.txt').readline()
n = len(s)
l = 0
r = 0
cnt_2025 = 0
if s[0] == 'Y':
    cnt_y = 1
else:
    cnt_y = 0
answ = 0
while r + 1 < n:
    r += 1
    if s[r] == 'Y':
        cnt_y += 1
    if r - l + 1 >= 4 and s[r - 3:r + 1] == '2025':
        cnt_2025 += 1
    if cnt_y > 80:
        while s[l] != 'Y':
            if r - l + 1 >= 4 and s[l:l + 4] == '2025':
                cnt_2025 -= 1
            l += 1
        l += 1
        cnt_y -= 1
    if cnt_y == 80 and cnt_2025 >= 90:
        answ = max(answ, r - l + 1)
print(answ)