#define _CRT_SECURE_NO_WARNINGS
#define debug(tl) cerr<<#tl<<' '<<tl<<'\n';
#include "bits/stdc++.h"
using namespace std;
#define all(d) d.begin(), d.end()
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef long double ld;
const int N = 2000;
int p[N];
void init(int n) {
    fill(p, p + n, -1);
}
int find(int x) {
    return p[x] < 0 ? x : p[x] = find(p[x]);
}
bool join(int a, int b) {
    a = find(a), b = find(b);
    if (a == b)
        return false;
    if (p[a] > p[b])
        swap(a, b);
    p[a] += p[b];
    p[b] = a;
    return true;
}
signed main() {
#ifdef _DEBUG
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n;
    cin >> n;
    struct edge {
        int u, v, w;
        bool operator<(const edge &other) {
            return w < other.w;
        }
    };
    vector<edge> e;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            int x;cin >> x;
            if (x)e.push_back({ i,j, x });
        }
    }
    sort(all(e));
    init(n);
    vector<edge> ans;
    for (int i = 0; i < (int)e.size(); i++) {
        if (join(e[i].u, e[i].v)) {
            ans.emplace_back(e[i]);
            if ((int)ans.size() == n - 1)break;
        }
    }
    cout << n << '\n';
    for (const edge& i : ans) {
        cout << i.u + 1 << ' ' << i.v + 1 << ' ' << i.w << '\n';
    }
}