#include<bits/stdc++.h>
using namespace std;
const int MOD=998244353;
int main()
{
	ios_base::sync_with_stdio(false);
	long long n;
	cin>>n;
	if(n==1)
	{
		cout<<"POSSIBLE\n1 1\n";
	}
	else if(n%2==1 or n<=4)
	{
		cout<<"IMPOSSIBLE\n";
	}
	else if(n<18)
	{
		cout<<"POSSIBLE\n";
		vector<int> vr(n+5),vc(n+5);
		int sx,sy;
		vector<int> dx={1,3,3,1,-1,-3,-3,-1},dy={-3,-1,1,3,3,1,-1,-3};
		vector<pair<int,int>> sol;
		auto chk=[&](int x){return 1<=x and x<=n;};
		function<void(int,int,int)> dfs=[&](int x,int y,int dep)
		{
	//		cerr<<"dfs "<<x<<' '<<y<<' '<<dep<<endl;
			sol.emplace_back(x,y);
			if(dep==n)
			{
				for(int i=0;i<8;i++)
				{
					if(x+dx[i]==sx and y+dy[i]==sy)
					{
						for(auto [xx,yy]:sol)
							cout<<xx<<' '<<yy<<endl;
						exit(0);
					}
				}
				sol.pop_back();
				return;
			}
			vr[x]=1;vc[y]=1;
			for(int i=0;i<8;i++)
			{
				if(chk(x+dx[i]) and chk(y+dy[i]) and vr[x+dx[i]]==0 and vc[y+dy[i]]==0)
				{
					dfs(x+dx[i],y+dy[i],dep+1);
				}
			}
			vr[x]=0;vc[y]=0;
			sol.pop_back();
		};
		for(int i=1;i<=n;i++)
		{
			sx=1;sy=i;
			dfs(1,i,1);
		}
	}
	else if(n%4==2)
	{
		cout<<"POSSIBLE\n";
		cout<<1<<' '<<2<<endl;
		cout<<4<<' '<<1<<endl;
		cout<<5<<' '<<4<<endl;
		for(int i=8;i<=n;i+=4)
		{
			cout<<i<<' '<<i-5<<"\n";
			cout<<i+1<<' '<<i-2<<"\n";
		}
		cout<<n<<' '<<n-1<<endl;
		cout<<n-3<<' '<<n<<endl;
		cout<<n-4<<' '<<n-3<<endl;
		for(int i=n-7;i>=1;i-=4)
		{
			cout<<i<<' '<<i+5<<"\n";
			cout<<i-1<<' '<<i+2<<"\n";
		}
	}
	else //n%4==0
	{
		cout<<"POSSIBLE\n";
		cout<<1<<' '<<6<<endl;
		cout<<2<<' '<<3<<endl;
		cout<<5<<' '<<2<<endl;
		for(int i=8;i<n;i+=4)
		{
			cout<<i<<' '<<i-7<<"\n";
			cout<<i+1<<' '<<i-4<<"\n";
		}
		cout<<n<<' '<<n-7<<endl;
		cout<<n-1<<' '<<n-4<<endl;
		cout<<n-2<<' '<<n-1<<endl;
		cout<<n-5<<' '<<n<<endl;
		cout<<n-6<<' '<<n-3<<endl;
		for(int i=n-9;i>=7;i-=4)
		{
			cout<<i<<' '<<i+7<<"\n";
			cout<<i-1<<' '<<i+4<<"\n";
		}
		cout<<3<<' '<<10<<endl;
		cout<<4<<' '<<7<<endl;
	}
	return 0;
}