//#pragma GCC optimize ("Ofast")
//#pragma GCC target("avx2")
//#pragma GCC optimize("unroll-loops")
//#include <x86intrin.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>

#define PI 3.141592653589793L
#define FAST ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
// Use for file I/O;
#define FIN string _fname = "input"; \
			string _is = _fname + ".in", _os = _fname + ".out"; \
			freopen(_is.c_str(), "r", stdin); \
			freopen(_os.c_str(), "w", stdout);

#define FIN2 freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);

#define all(x) (x).begin(), (x).end()
#define allr(x) (x).rbegin(), (x).rend()
#define gsize(x) (int)((x).size())

using namespace std;
//using namespace __gnu_pbds;
//typedef gp_hash_table<int, int, hash<int>> ht;

const char nl = '\n';

typedef long long ll;
typedef long double ld;
// typedef unsigned int uint;
typedef unsigned long long ull;

const ll inf = 1e9 + 10;
const ll inf2 = 1e18 + 99LL;
const ld inf3 = 1e14;
const ll mod = 1e9 + 7;
const ld eps = 1e-9;

const int logn = 20, maxn = 2000, maxm = 1000001, maxn2 = 3;

int a[maxn][maxn];
int c[maxn], p[maxn];

int ti;
void solve(vector<int> x, int tp = -1) {
    if (gsize(x) == 1) {
        p[x[0]] = tp;
        return;
    } else if (gsize(x) == 0) return;
    
    int m = gsize(x);
    int tv = 0, v2 = inf;
    for (int i = 0; i < m; i++) {
        for (int j = 1; j < m; j++) {
            tv = max(tv, a[x[i]][x[j]]);
            v2 = min(v2, a[x[i]][x[j]]);
        }
    }
    
    c[ti] = tv;
    p[ti] = tp;
    
    ti++;
    if (v2 == tv) {
        for (int v: x) {
            p[v] = ti - 1;
        }
        return;
    }
        
    int cti = ti - 1;
    vector<bool> used(m);
    for (int i = 0; i < m; i++) {
        if (used[i]) continue;
        used[i] = true;
        vector<int> v = {x[i]};
        for (int j = i + 1; j < m; j++) {
            if (!used[j]) {
                if (a[x[i]][x[j]] < tv) {
                    used[j] = true;
                    v.push_back(x[j]);
                }
            }
        }
        solve(v, cti);
    }
}
    
int main() {
	FAST;
    
    int n;
    cin >> n;
    ti = n;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) cin >> a[i][j];
        c[i] = a[i][i];
    }
    
    vector<int> s(n);
    for (int i = 0; i < n; i++) s[i] = i;
    solve(s);
    
    cout << ti << nl;
    for (int i = 0; i < ti; i++) cout << c[i] << ' ';
    cout << nl << n + 1 << nl;
    for (int i = 0; i < ti; i++) {
        if (i != n) cout << i + 1 << ' ' << p[i] + 1 << nl;
    }
}
