#include<bits/stdc++.h>
	
	#define pb push_back
	#define x first
	#define y second
	#define all(a) (a).begin(), (a).end()
	
	using namespace std;
	
	typedef long long ll;
	typedef pair<int, int> ii;
	
	const int maxn = 1025;
	
	int n;
	vector<int> r, c, d1, d2;
	vector<ii> ans;
	
	int check(int x, int y) {
		return (r[x] + c[y] + d1[x + y] + d2[x - y + n] + 1) % 2;
	}
	
	int play(int x, int y) {
		//if(!check(x, y)) {
		//	cout << "err\n";
	//		exit(0);
	//	}
		if(ans.size() > 5) {
			while(1) {}	
		}
		ans.pb({x, y});
		r[x]++, c[y]++, d1[x + y]++, d2[x - y + n]++;
	}
	
	void resi4() {
		play(0, 1);
		play(1, 3);
		play(0, 2);
		play(1, 0);
		play(1, 1);
		play(2, 3);
		play(0, 3);
		play(2, 0);
		play(2, 1);
		play(2, 2);
		play(3, 0);
		play(3, 2);
		play(3, 1);
		play(3, 3);
	}
	
	void resi3() {
		play(1, 2);
		play(2, 0);
		play(1, 1);
		play(0, 0);
		play(2, 2);
		play(2, 1);
		play(0, 1);
		play(0, 2);
		play(1, 0);	
	}
		
	void rek(int n) {
		if(n <= 2) {play(0, 0);return;}
		if(n == 3) {resi3();return;}
		if(n == 4) {resi4();return;}
		rek(n - 2);
		
		for(int i = 0;i < n - 3;i++) {
			if(check(i, n - 1))
				play(i, n - 1), play(i, n - 2);
			else play(i, n - 2), play(i, n - 1);
			
			if(check(n - 1, i))
				play(n - 1, i), play(n - 2, i);
			else play(n - 2, i), play(n - 1, i);
		}
		
		if(n % 2 == 1) {
			play(n - 2, n - 1);
			play(n - 3, n - 2);
			play(n - 1, n - 2);
			play(n - 2, n - 2);
			play(n - 3, n - 1);
			play(n - 1, n - 3);
			play(n - 2, n - 3);
			play(n - 1, n - 1);	
		} else {
			play(n - 3, n - 1);	
			play(n - 3, n - 2);
			play(n - 2, n - 1);
			play(n - 2, n - 3);
			play(n - 1, n - 3);
			play(n - 2, n - 2);
			play(n - 1, n - 2);
			play(n - 1, n - 1);
		}
	}
	
	int main() {
		cin >> n;
		vector<int> v(2 * n, 0);
		r = c = d1 = d2 = v;
		rek(n);
		return 0;
		cout << ans.size() << "\n";
		for(ii p : ans)
			cout << p.x + 1 << " " << p.y + 1 << "\n";
		return 0;
	}