#include<bits/stdc++.h>
using namespace std;
class dsu {
public:
vector<int> par, ct;
dsu(int sz) {
ct.resize(sz, 1);
par.resize(sz);
iota(par.begin(), par.end(), 0);
}
int get_par(int nd) {
return (par[nd] == nd ? nd : get_par(par[nd]));
}
bool Merge(int a, int b) {
a = get_par(a), b = get_par(b);
if (a == b) return false;
if (ct[a] < ct[b]) swap(a, b);
ct[a] += ct[b];
par[b] = a;
return true;
}
};
int main () {
ios_base::sync_with_stdio(0);
cin.tie(0);
int type, n;
cin >> type >> n;
vector<vector<int>> adj(n, vector<int>(n));
for (int i = 0; i < n; ++i) for (int j = 0; j < n; ++j) cin >> adj[i][j];
dsu graph(n);
vector<pair<int, int>> edges;
vector<vector<int>> g(n);
auto add_edge = [&](int val) {
for (int i = 0; i < n; ++i) for (int j = 0; j < n; ++j) {
if (adj[i][j] == val && graph.Merge(i, j)) {
edges.emplace_back(i, j);
g[i].push_back(j);
g[j].push_back(i);
}
}
};
add_edge(1); add_edge(2);
struct same { int sr, l, r; };
vector<vector<same>> ct(n);
for (int i = 0; i < n; ++i) {
vector<int> len(n);
function<void(int, int)> dfs = [&](int nd, int par) {
for (auto el : g[nd]) {
if (el == par) continue;
len[el] = len[nd] + 1;
if (adj[i][el] == adj[i][nd]) {
ct[len[el]].push_back(same{i, nd, el});
}
dfs(el, nd);
}
};
dfs(i, -1);
}
dsu col(n);
vector<vector<bool>> vis(n, vector<bool>(n));
for (int i = 0; i < n; ++i) {
for (auto el : ct[i]) {
if (vis[el.l][el.r]) continue;
vis[el.l][el.r] = true;
col.Merge(el.sr, el.r);
}
}
for (int i = 0; i < n; ++i) cout << col.get_par(i) + 1 << ' ';
for (auto el : edges) cout << '\n' << el.first + 1 << ' ' << el.second + 1;
}
