#include<bits/stdc++.h>
#define rep(i,a,b) for (int i = (a); i <= (b); ++i)
#define drep(i,a,b) for (int i = (a); i >= (b); --i)
#define LL long long
#define pii pair<int,int>
#define pll pair<LL,LL>
#define fi first
#define se second
#define eb emplace_back
#define mp make_pair
using namespace std;
LL read() {
	LL x = 0,y = 1; char ch = getchar(); while (!isdigit(ch)) {if (ch == '-') y = -y; ch = getchar();}
	while (isdigit(ch)) {x = x*10+ch-'0'; ch = getchar();} return x*y;
}
namespace qiqi {
	const int N = 1e5+5; int n,m,vx[N],vy[N],tl,dx[8] = {1,3,3,1,-1,-3,-3,-1},dy[8] = {3,1,-1,-3,-3,-1,1,3}; pii q[N]; vector<pii> ans;
	bool chk(int x,int y) {
		return x > 0 && y > 0 && x <= n && y <= n && !vx[x] && !vy[y];
	}
	bool dfs(int x,int y) {
		q[++tl] = mp(x,y);
		vx[x] = vy[y] = 1;
		if (tl == n) {
			rep(i,1,tl) ans.eb(q[i]);
			return 1;
		}
		rep(i,0,7) if (chk(x+dx[i],y+dy[i])) {
			if (dfs(x+dx[i],y+dy[i])) return 1;
		}
		--tl; vx[x] = vy[y] = 0;
		return 0;
	}
	void print() {
		puts("POSSIBLE");
		for (auto p:ans) printf("%d %d\n",p.fi,p.se);
	}
	void fail() {
		puts("IMPOSSIBLE");
	}
	void main() {
		n = read();
		if (n < 11) {
			rep(i,1,n) rep(j,1,n) {
				if (dfs(i,j)) {
					return print(); 
				}
			}
			return fail();
		}
		while (n > 11) {
			ans.eb(mp(n,n));
			ans.eb(mp(n-1,n-3));
			ans.eb(mp(n-4,n-4));
			ans.eb(mp(n-5,n-1));
			ans.eb(mp(n-2,n-2));
			ans.eb(mp(n-3,n-5));
			n -= 6;
		}
		if (!dfs(n,n)) return fail();
		print();
	}
}
int main() {
	qiqi::main(); return 0;
}