#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<utility>
#include<algorithm>
#include<map>
#include<vector>
#include<list>
#include<functional>
#include<string>
using namespace std;
int u[10005], v[10005], w[10005], first[105], nxt[10005];
int n, m;
bool control[105],visited[105];
int percentage[105];
void dfs(int node) {
    if (visited[node])return;
    visited[node] = true;
    for (int e = first[node]; e != -1; e = nxt[e]) {
        percentage[v[e]] += w[e];
        if (percentage[v[e]] > 50) {
            control[v[e]] = true;
            dfs(v[e]);
        }
    }
}
int main() {
    memset(first, -1, sizeof(first));
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> u[i] >> v[i] >> w[i];
        nxt[i] = first[u[i]];
        first[u[i]] = i;
        m = max(m, max(u[i], v[i]));
    }
    for (int i = 1; i <= m; i++) {
        memset(visited, false, sizeof(visited));
        memset(control, false, sizeof(control));
        memset(percentage, 0, sizeof(percentage));
        dfs(i);
        for (int j = 1; j <= m; j++) {
            if (i != j&&control[j])cout << i << " " << j << endl;
        }
    }
}