MOD = 998244353
n = int(input())
dp = [[0] * (n + 1) for _ in range(n + 1)]
dp[0][0] = 1
for i in range(n):
    for j in range(n):
        dp[i][j] %= MOD
        dp[i + 1][j] += dp[i][j] * 25
        dp[i + 1][j + 1] += dp[i][j]
ans = 0
for i in range(n + 1):
    ans += dp[n][i] * (i // 3)
print(ans)