N = int(input())
mod = 998244353
dp = [[0] * 3005 for i in range(3005)]
dp[0][0] = 1
for i in range(N):
    for j in range(i + 1):
        dp[i + 1][j + 1] += dp[i][j]
        dp[i + 1][j + 1] %= mod
        dp[i + 1][j] += dp[i][j] * 25
        dp[i + 1][j] %= mod
        
ans = 0
for i in range(N + 1):
    ans += dp[N][i] * (i//3)
    ans %= mod
print(ans)