N = int(input())
dp = [[0 for _ in range(N + 2)] for _ in range(N + 1)]
dp[0][0] = 1

mod = 998244353
for i in range(N):
    for j in range(N + 1):
        dp[i + 1][j + 1] = (dp[i + 1][j + 1] + dp[i][j]) % mod
        dp[i + 1][j] = (dp[i + 1][j] + dp[i][j] * 25) % mod

ans = 0
for j in range(N + 1):
    ans = (ans + dp[N][j] * (j // 3)) % mod
print(ans)