1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
#include <bits/stdc++.h>
using namespace std;

int k, n;
int G[105][2];

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	
	cin >> k;
	
	while ((1<<n) <= k)
		n++;
	n = 2*n-1;
	
	for (int i = 1; i < n; i += 2)
	{
		G[i][0] = i+1;
		G[i][1] = i+2;
		G[i+1][0] = i+2;
		G[i+1][1] = -1;
	}
	G[n][0] = n+1;
	G[n][1] = G[n+1][0] = G[n+1][1] = -1;
	
	
	bitset <32> B = k;
	for (int i = 2; i < n; i += 2)
		if (B[i/2-1])
			G[i][1] = n+1;
	
	cout << n+1 << '\n';
	for (int i = 1; i <= n+1; i++)
		cout << G[i][0] << ' ' << G[i][1] << '\n';
}