t, m, o, l, e = 1, 0, 0, 0, 0
for i in range(int(input())):
    t, m, o, l, e = (v % 998244353 for v in (
        t * 26,
        m * 26 + t,
        o * 26 + m,
        l * 26 + o,
        e * 26 + l,
    ))
print(e)