hack

#include<bits/stdc++.h>
#define Gc() getchar() 
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define PB push_back
#define fi first
#define se second
using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;
using namespace std;const int N=2e5+5,M=N*60+5,K=N*4+5,mod=998244353,Mod=mod-1;const db eps=1e-9;const ll INF=1e18+7;mt19937 rnd(time(0));
int A[N];
int main(){
	freopen("1.in","w",stdout);
	int i,n=50000;printf("%d\n",n);for(int i=1;i<=4*n;i++) A[i]=(i-1)/4+1;
	shuffle(A+1,A+4*n+1,rnd);for(i=1;i<=n/2;i++){
		int x=i*2-1,y=i*2;
		if(i<n/2)printf("%d %d %d %d %d %d %d %d ",x,x,y,x,y,y,x,y);
		else printf("%d %d %d %d %d %d %d %d ",x,x,x,y,y,y,y,x);
	} 
}