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#include <bits/stdc++.h>
using namespace std;

#define endl '\n'
#define L long long
#define MP make_pair
#define REP(i, n) for(int i = 0; i < n; ++i)
#define REPR(i, n) for(int i = n - 1; i >= 0; --i)
#define FOR(i, a, b) for(int i = a; i < b; ++i)
#define FORR(i, a, b) for(int i = b - 1; i >= a; --i)
#define EB emplace_back
#define ST first
#define ND second
#define S size()
#define RS resize

using VI = vector<int>;
using VVI = vector<VI>;
using PI = pair<int, int>;
using VPI = vector<PI>;
using VVPI = vector<VPI>;
using VL = vector<L>;
using VVL = vector<VL>;
using VB = vector<bool>;
using VVB = vector<VB>;

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    int k;
    cin >> k;
	
    VPI g(2);
    g[0] = MP(1, -2);
    g[1] = MP(-2, -2);
    
    int p = 1;
    int i = 0;
    while (p * 2 <= k)
    {
    	i++;
    	g.EB(2 * i + 1, -2);
    	g.EB(-2, -2);
    	g[2 * i - 1] = MP(2 * i, -2);
    	g[2 * i - 2] = MP(2 * i - 1, 2 * i);
    	p *= 2;
	}
	
	k -= p;
	REP(j, i)
		if ((1 << j) & k)
			g[2 * j + 1].ND = 2 * i + 1;
	
	cout << int(g.S) << endl;
	REP(j, int(g.S))
		cout << g[j].ST + 1 << ' ' << g[j].ND + 1 << endl;
}