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

int32_t main(){
    ios::sync_with_stdio(false);
    int k,n=94;
    cin >> k;
    int cur = 1;
    vector<pair<int,int> > edg(n+1,{-1,-1});
    for(int i=1;i<n;i++)
        edg[i].first = i+1;
    
    while(k > 1) {
        if(k%2 == 1) {
            edg[cur].second = n;
            cur++;
        }
        edg[cur].second = cur+2;
        cur += 2;
        k/=2;
    }
    cout<<cur+2<<"\n";
    for(int i=1;i<=cur+1;i++)
        cout<<min(cur+2,edg[i].first)<<" "<<min(cur+2,edg[i].second)<<"\n";
    cout<<"-1 -1\n";
        
}