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

typedef long long LL;
typedef long double LD;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;

#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()

template<typename _T> inline void _DBG(const char *s, _T x) { cerr << s << " = " << x << "\n"; }
template<typename _T, typename... args> void _DBG(const char *s, _T x, args... a) { while(*s != ',') cerr << *s++; cerr << " = " << x << ','; _DBG(s + 1, a...); }

#ifdef LOCAL
#define _upgrade ios_base::sync_with_stdio(0);
#define DBG(...) _DBG(#__VA_ARGS__, __VA_ARGS__)
#else
#define _upgrade ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define DBG(...) (__VA_ARGS__)
#define cerr if(0) cout
#endif

// ********************** CODE ********************** //

const int N = 101;

vector<int> G[N];

int main()
{
    _upgrade
    
    int k;
    cin >> k;

    int cnt = 1;
    for(int i = 0; i < 30; i++)
    {
        G[cnt].push_back(cnt + 1);
        G[cnt].push_back(cnt + 2);
        G[cnt + 1].push_back(cnt + 3);
        G[cnt + 2].push_back(cnt + 3);
        cnt += 3;
    }
    G[cnt].push_back(cnt + 1);
    cnt += 2;
    for(int i = 0; i < 30; i++)
    {
        if((k >> i) & 1)
            G[3 * i + 2].push_back(cnt);
    }

    cout << cnt << "\n";
    for(int i = 1; i <= cnt; i++)
    {
        cout << (sz(G[i]) > 0 ? G[i][0] : -1) << " ";
        cout << (sz(G[i]) > 1 ? G[i][1] : -1) << "\n";
    }

    return 0;
}