#include <iostream>
#include <sstream>
#include <cstdio>
#include <vector>
#include <cmath>
#include <queue>
#include <string>
#include <cstring>
#include <cassert>
#include <iomanip>
#include <algorithm>
#include <set>
#include <map>
#include <ctime>
#include <cmath>

#define forn(i, n) for(int i=0;i<n;++i)
#define fore(i, l, r) for(int i = int(l); i <= int(r); ++i)
#define sz(v) int(v.size())
#define all(v) v.begin(), v.end()
#define pb push_back
#define mp make_pair
#define x first
#define y1 ________y1
#define y second
#define ft first
#define sc second
#define pt pair<int, int>

template<typename X> inline X abs(const X& a) { return a < 0? -a: a; }
template<typename X> inline X sqr(const X& a) { return a * a; }

typedef long long li;
typedef long double ld;

using namespace std;

const int INF = 1000 * 1000 * 1000;
const ld EPS = 1e-9;
const ld PI = acos(-1.0);

const int N = 100 * 1000 + 13;

set<pair<int, int> > was;
int n;
vector<pair<int, int> > a;
vector<int> d[N];
int cnt[N];

inline void read() {
    cin >> n;
    for (int i = 0; i < n; i++) {
        int x, y, z;
        cin >> x >> y >> z;
        a.pb(mp(x, i));
        a.pb(mp(y, i));
        a.pb(mp(z, i));
        d[i].pb(x);
        d[i].pb(y);
        d[i].pb(z);
        sort(all(d[i]));
    }
}

inline void solve() {
    sort(all(a));
    int now = 0;
    int ans = INF;
    for (int i = 0; i < sz(a); i++) {
        int idx = a[i].sc;
        if (cnt[idx] < 2) {
            was.insert(a[i]);
            cnt[idx]++;
            if (cnt[idx] == 2) now++;
        } else {
            was.erase(mp(d[idx][0], idx));
            was.insert(a[i]);
        }
        if (now == n) {
            ans = min(ans, (*was.rbegin()).ft - (*was.begin()).ft);
        }
    }
    cout << ans << endl;
}

int main () {
#ifdef fcspartakm
    freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
#endif
    srand(time(NULL));
    cerr << setprecision(10) << fixed;

    read();
    solve();

    //cerr << "TIME: " << clock() << endl;
}