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#include <bits/stdc++.h>

using namespace std;

#define ALL(x) (x).begin(), (x).end()

template<class C> void mini(C &a5, C b5) { a5 = min(a5, b5); }
template<class C> void maxi(C &a5, C b5) { a5 = max(a5, b5); }

#ifdef LOCAL
const bool debug = true;
#else
const bool debug = false;
#define cerr if (true) {} else cout
#endif

#define int long long
#define double long double

const int INF = 1e18;
const int mod = 1e9 + 7;

int n = 1;
pair<int, int> kra[1001000];

void algo(int k) {
	if (k == 1) return;
	
	kra[n] = {n + 1, -1 - k % 2};
	n++;
	
	kra[n] = {n + 1, n + 2};
	n++;
	
	kra[n] = {n + 1, -1};
	n++;
	
	algo(k / 2);
}

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    int k;
	cin >> k;
    
    algo(k);
    kra[n] = {n + 1, -1};
    n++;
    kra[n] = {-1, -1};
    
    cout << n << "\n";
    for (int i = 1; i <= n; i++) {
		if (kra[i].first == -2) kra[i].first = n;
		if (kra[i].second == -2) kra[i].second = n;
		
		cout << kra[i].first << " " << kra[i].second << "\n";
	}
    
    return 0;
}/*

*/