Language: C++


	Init();
	cin>>n;
	ll res=Pow(3,n);
	for(int i=n/2+1;i<=n;i++) res=(res-2*nCk(n,i)*Pow(2,n-i)%mod+mod)%mod;
	cout<<res<<endl;
}#include <bits/stdc++.h>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<int,P> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=998244353;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

ll Pow(ll n,ll p){
	ll r=1;
	for(;p>0;p>>=1){
		if(p&1) r=(r*n)%mod;
		n=(n*n)%mod;
	}
	return r;
}

const int M=10000005;
ll F[M];

void Init(){
	F[0]=1;
	for(int i=1;i<M;i++) F[i]=F[i-1]*i%mod;
}

ll Div(ll n,ll m){
	return n*Pow(m,mod-2)%mod;
}

ll nCk(ll n,ll k){
	return Div(F[n],F[n-k]*F[k]%mod);
}

int n;

int main(){
	Init();
	cin>>n;
	ll res=Pow(3,n);
	for(int i=n/2+1;i<=n;i++) res=(res-2*nCk(n,i)*Pow(2,n-i)%mod+mod)%mod;
	cout<<res<<endl;
}

Compiler output:
a.cc:7:2: error: stray '#' in program
    7 | }#include <bits/stdc++.h>
      |  ^
a.cc:2:15: error: expected constructor, destructor, or type conversion before ';' token
    2 |         Init();
      |               ^
a.cc:3:9: error: 'cin' does not name a type
    3 |         cin>>n;
      |         ^~~
a.cc:4:9: error: 'll' does not name a type
    4 |         ll res=Pow(3,n);
      |         ^~
a.cc:5:9: error: expected unqualified-id before 'for'
    5 |         for(int i=n/2+1;i<=n;i++) res=(res-2*nCk(n,i)*Pow(2,n-i)%mod+mod)%mod;
      |         ^~~
a.cc:5:25: error: 'i' does not name a type
    5 |         for(int i=n/2+1;i<=n;i++) res=(res-2*nCk(n,i)*Pow(2,n-i)%mod+mod)%mod;
      |                         ^
a.cc:5:30: error: 'i' does not name a type
    5 |         for(int i=n/2+1;i<=n;i++) res=(res-2*nCk(n,i)*Pow(2,n-i)%mod+mod)%mod;
      |                              ^
a.cc:6:9: error: 'cout' does not name a type
    6 |         cout<<res<<endl;
      |         ^~~~
a.cc:7:1: error: expected declaration before '}' token
    7 | }#include <bits/stdc++.h>
      | ^
a.cc:7:3: error: 'include' does not name a type
    7 | }#include <bits/stdc++.h>
      |   ^~~~~~~
a.cc:13:9: error: 'pair' does not name a type
   13 | typedef pair<int,int> P;
      |         ^~~~
a.cc:14:9: error: 'pair' does not name a type
   14 | typedef pair<double,double> pdd;
      |         ^~~~
a.cc:15:9: error: 'pair' does not name a type
   15 | typedef pair<ll,ll> pll;
      |         ^~~~
a.cc:16:9: error: 'vector' does not name a type
   16 | typedef vector<int> vi;
      |         ^~~~~~
a.cc:17:9: error: 'vector' does not name a type
   17 | typedef vector<vi> vvi;
      |         ^~~~~~
a.cc:18:9: error: 'vector' does not name a type
   18 | typedef vector<double> vd;
      |         ^~~~~~
a.cc:19:9: error: 'vector' does not name a type
   19 | typedef vector<vd> vvd;
      |         ^~~~~~
a.cc:20:9: error: 'vector' does not name a type
   20 | typedef vector<ll> vl;
      |         ^~~~~~
a.cc:21:9: error: 'vector' does not name a type
   21 | typedef vector<vl> vvl;
      |         ^~~~~~
a.cc:22:9: error: 'vector' does not name a type
   22 | typedef vector<string> vs;
      |         ^~~~~~
a.cc:23:9: error: 'vector' does not name a type
   23 | typedef vector<P> vp;
      |         ^~~~~~
a.cc:24:9: error: 'vector' does not name a type
   24 | typedef vector<vp> vvp;
      |         ^~~~~~
a.cc:25:9: error: 'vector' does not name a type
   25 | typedef vector<pll> vpll;
      |         ^~~~~~
a.cc:26:9: error: 'pair' does not name a type
   26 | typedef pair<int,P> pip;
      |         ^~~~
a.cc:27:9: error: 'vector' does not name a type
   27 | typedef vector<pip> vip;
      |         ^~~~~~
a.cc:30:17: error: 'acos' was not declared in this scope
   30 | const double pi=acos(-1);
      |                 ^~~~
a.cc: In function 'int main()':
a.cc:64:9: error: 'cin' was not declared in this scope
   64 |         cin>>n;
      |         ^~~
a.cc:67:9: error: 'cout' was not declared in this scope
   67 |         cout<<res<<endl;
      |         ^~~~
a.cc:67:20: error: 'endl' was not declared in this scope
   67 |         cout<<res<<endl;
      |                    ^~~~