#include<bits/stdc++.h>
#define lowbit(x) (x & (-x))
#define endl "\n"
#define ll long long
#define int long long
#define ull unsigned long long
#define fi first
#define se second
using namespace std;
#define pii pair<int, int>
#define rep(i, a, b) for(int i = a; i <= b; i ++ )
#define pre(i, a, b) for(int i = a; i >= b; i -- )
#define IOS ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
mt19937_64 rnd(time(0));
const int N = 1e6 + 10;
int n;
vector<int>p[N];
int sz[N], f[N], depth[N], ma[N];
pair<int, int>ans[N];
void dfs1(int u, int fa)
{
    sz[u] = 1, f[u] = fa, depth[u] = depth[fa] + 1;
    for(auto j : p[u])
    {
        if(j == fa) continue;
        dfs1(j, u);
        sz[u] += sz[j];
        if(sz[j] > ma[u]) ma[u] = sz[j];
    }
}
void dfs2(int u, int fa)
{
    int ff = 0;
    for(auto j : p[u])
    {
        if(j == fa) continue;
        dfs2(j, u);
        ff = 1;
    }
    if(!ff) 
    {
        ans[u].first = u;
        return;
    }
    for(auto j : p[u])
    {
        if(j == fa) continue;
        int d = ans[j].first;
        if(ans[j].second && depth[ans[j].second] > depth[d]) d = ans[j].second;
        int e = 0;
        while(1)
        {
            int w = ma[d];
            w = max(w, sz[u] - sz[d]);
            if(w * 2 <= sz[u])
            {
                if(ans[u].first == d || ans[u].second == d) break;
                if(!ans[u].first) ans[u].first = d;
                else ans[u].second = d;
                e = 1;
            }
            else if(e) break;
            if(d == u) break;
            d = f[d];
            if(ans[u].first && ans[u].second) break;
        }
    }
}
void solve()
{
    cin >> n;
    rep(i, 1, n - 1)
    {
        int u, v;
        cin >> u >> v;
        p[u].push_back(v);
        p[v].push_back(u);
    }
    dfs1(1, 0);
    dfs2(1, 0);
    rep(u, 1, n)
    {
        if(ans[u].first && ans[u].second) swap(ans[u].first, ans[u].second);
        cout << ans[u].first << " ";
        if(ans[u].second) cout << ans[u].second;
        cout << endl;
    }
}
signed main()
{
    IOS;
    int _;
    _ = 1;
    // cin >> _;
    while(_ -- )
    {
        solve();
    }
	return 0;
}