mod = 998244353

N = int(input())

# dp[i][j]: i番目まで見てconcon...のj番目まで完成
dp = [0]*(N+1)
dp[0] = 1
for i in range(N):
  dp2 = [0]*(N+1)
  for j in range(i+1):
    dp2[j] += dp[j] * 25
    dp2[j] %= mod
    dp2[j+1] += dp[j]
    dp2[j+1] %= mod
    
  dp = dp2
  
ans = 0
for i in range(3,N+1):
  ans += dp[i] * (i//3)
  ans %= mod
  
print(ans)