#pragma region Macros
#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define rep2(i, a, b) for(ll i = a; i <= b; ++i)
#define rep(i, n) for(ll i = 0; i < n; ++i)
#define rep3(i, a, b) for(ll i = a; i >= b; --i)
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define eb emplace_back
#define vi vector<int>
#define vll vector<ll>
#define vpi vector<pii>
#define vpll vector<pll>
#define overload2(_1, _2, name, ...) name
#define vec(type, name, ...) vector<type> name(__VA_ARGS__)
#define VEC(type, name, size)                                                                                                                                  \
    vector<type> name(size);                                                                                                                                   \
    IN(name)
#define vv(type, name, h, ...) vector<vector<type>> name(h, vector<type>(__VA_ARGS__))
#define VV(type, name, h, w)                                                                                                                                   \
    vector<vector<type>> name(h, vector<type>(w));                                                                                                             \
    IN(name)
#define vvv(type, name, h, w, ...) vector<vector<vector<type>>> name(h, vector<vector<type>>(w, vector<type>(__VA_ARGS__)))
#define fi first
#define se second
#define all(c) begin(c), end(c)
#define ios ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define lb(c, x) distance((c).begin(), lower_bound(all(c), (x)))
#define ub(c, x) distance((c).begin(), upper_bound(all(c), (x)))
using namespace std;
template <class T> using pq = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vector<T>, greater<T>>;
#define Size(c) (int)(c).size()
#define INT(...)                                                                                                                                               \
    int __VA_ARGS__;                                                                                                                                           \
    IN(__VA_ARGS__)
#define LL(...)                                                                                                                                                \
    ll __VA_ARGS__;                                                                                                                                            \
    IN(__VA_ARGS__)
#define ULL(...)                                                                                                                                               \
    ull __VA_ARGS__;                                                                                                                                           \
    IN(__VA_ARGS__)
#define STR(...)                                                                                                                                               \
    string __VA_ARGS__;                                                                                                                                        \
    IN(__VA_ARGS__)
#define CHR(...)                                                                                                                                               \
    char __VA_ARGS__;                                                                                                                                          \
    IN(__VA_ARGS__)
#define DBL(...)                                                                                                                                               \
    double __VA_ARGS__;                                                                                                                                        \
    IN(__VA_ARGS__)
#define LD(...)                                                                                                                                                \
    ld __VA_ARGS__;                                                                                                                                            \
    IN(__VA_ARGS__)
int scan() { return getchar(); }
template <class T> void scan(T a) { cin >> a; }
void scan(int &a) { cin >> a; }
void scan(long long &a) { cin >> a; }
void scan(char &a) { cin >> a; }
void scan(double &a) { cin >> a; }
void scan(long double &a) { cin >> a; }
void scan(char a[]) { scanf("%s", a); }
void scan(string &a) { cin >> a; }
template <class T> void scan(vector<T> &);
template <class T, size_t size> void scan(array<T, size> &);
template <class T, class L> void scan(pair<T, L> &);
template <class T, size_t size> void scan(T (&)[size]);
template <class T> void scan(vector<T> &a) {
    for(auto &i : a) scan(i);
}
template <class T> void scan(deque<T> &a) {
    for(auto &i : a) scan(i);
}
template <class T, size_t size> void scan(array<T, size> &a) {
    for(auto &i : a) scan(i);
}
template <class T, class L> void scan(pair<T, L> &p) {
    scan(p.first);
    scan(p.second);
}
template <class T, size_t size> void scan(T (&a)[size]) {
    for(auto &i : a) scan(i);
}
template <class T> void scan(T &a) { cin >> a; }
void IN() {}
template <class Head, class... Tail> void IN(Head &head, Tail &... tail) {
    scan(head);
    IN(tail...);
}
string stin() {
    string s;
    cin >> s;
    return s;
}
template <class T, class S> inline bool chmax(T &a, S b) {
    if(a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T, class S> inline bool chmin(T &a, S b) {
    if(a > b) {
        a = b;
        return 1;
    }
    return 0;
}
vi iota(int n) {
    vi a(n);
    iota(all(a), 0);
    return a;
}
template <class T> void UNIQUE(vector<T> &x) {
    sort(all(x));
    x.erase(unique(all(x)), x.end());
}
int in() {
    int x;
    cin >> x;
    return x;
}
ll lin() {
    unsigned long long x;
    cin >> x;
    return x;
}
void print() { putchar(' '); }
void print(bool a) { cout << a; }
void print(int a) { cout << a; }
void print(long long a) { cout << a; }
void print(char a) { cout << a; }
void print(string &a) { cout << a; }
void print(double a) { cout << a; }
template <class T> void print(const vector<T> &);
template <class T, size_t size> void print(const array<T, size> &);
template <class T, class L> void print(const pair<T, L> &p);
template <class T, size_t size> void print(const T (&)[size]);
template <class T> void print(const vector<T> &a) {
    if(a.empty()) return;
    print(a[0]);
    for(auto i = a.begin(); ++i != a.end();) {
        cout << " ";
        print(*i);
    }
    cout << endl;
}
template <class T> void print(const deque<T> &a) {
    if(a.empty()) return;
    print(a[0]);
    for(auto i = a.begin(); ++i != a.end();) {
        cout << " ";
        print(*i);
    }
}
template <class T, size_t size> void print(const array<T, size> &a) {
    print(a[0]);
    for(auto i = a.begin(); ++i != a.end();) {
        cout << " ";
        print(*i);
    }
}
template <class T, class L> void print(const pair<T, L> &p) {
    cout << '(';
    print(p.first);
    cout << ",";
    print(p.second);
    cout << ')';
}
template <class T> void print(set<T> &x) {
    for(auto e : x) print(e), cout << " ";
    cout << endl;
}
template <class T> void print(multiset<T> &x) {
    for(auto e : x) print(e), cout << " ";
    cout << endl;
}
template <class T, size_t size> void print(const T (&a)[size]) {
    print(a[0]);
    for(auto i = a; ++i != end(a);) {
        cout << " ";
        print(*i);
    }
}
template <class T> void print(const T &a) { cout << a; }
int out() {
    putchar('\n');
    return 0;
}
template <class T> int out(const T &t) {
    print(t);
    putchar('\n');
    return 0;
}
template <class Head, class... Tail> int out(const Head &head, const Tail &... tail) {
    print(head);
    putchar(' ');
    out(tail...);
    return 0;
}
ll gcd(ll a, ll b) {
    while(b) {
        ll c = b;
        b = a % b;
        a = c;
    }
    return a;
}
ll lcm(ll a, ll b) {
    if(!a || !b) return 0;
    return a * b / gcd(a, b);
}
vector<pll> factor(ll x) {
    vector<pll> ans;
    for(ll i = 2; i * i <= x; i++)
        if(x % i == 0) {
            ans.push_back({i, 1});
            while((x /= i) % i == 0) ans.back().second++;
        }
    if(x != 1) ans.push_back({x, 1});
    return ans;
}
template <class T> vector<T> divisor(T x) {
    vector<T> ans;
    for(T i = 1; i * i <= x; i++)
        if(x % i == 0) {
            ans.pb(i);
            if(i * i != x) ans.pb(x / i);
        }
    return ans;
}
template <typename T> void zip(vector<T> &x) {
    vector<T> y = x;
    sort(all(y));
    for(int i = 0; i < x.size(); ++i) { x[i] = lb(y, x[i]); }
}
int popcount(ll x) { return __builtin_popcountll(x); }
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int n) { return uniform_int_distribution<int>(0, n - 1)(rng); }
template <typename T> void shuffle(vector<T> &v) {
    rep3(i, v.size() - 1, 1) { swap(v[i], v[rnd(i)]); }
}
#define endl '\n'
vector<string> YES{"NO", "YES"};
vector<string> Yes{"No", "Yes"};
vector<string> yes{"no", "yes"};

#ifdef _LOCAL
#undef endl
#define debug(x)                                                                                                                                               \
    cout << #x << ": ";                                                                                                                                        \
    print(x);                                                                                                                                                  \
    cout << endl;
void err() {}
template <class T> void err(const T &t) {
    print(t);
    cout << " ";
}
template <class Head, class... Tail> void err(const Head &head, const Tail &... tail) {
    print(head);
    putchar(' ');
    out(tail...);
}
#else
#define debug(x)
template <class... T> void err(const T &...) {}
#endif

template <typename T> struct edge {
    int from, to;
    T cost;
    int id;
    edge(int to, T cost) : from(-1), to(to), cost(cost) {}
    edge(int from, int to, T cost) : from(from), to(to), cost(cost) {}
    edge(int from, int to, T cost, int id) : from(from), to(to), cost(cost), id(id) {}
    edge &operator=(const int &x) {
        to = x;
        return *this;
    }
    operator int() const { return to; }
};
template <typename T> using Edges = vector<edge<T>>;

struct Graph : vector<vector<int>> {
    using vector<vector<int>>::vector;
    Graph(int n, int m) : vector(n) { read(m); }
    inline void add(int a, int b, bool directed = false) {
        (*this)[a].emplace_back(b);
        if(!directed) (*this)[b].emplace_back(a);
    }
    void read(int n = -1, int offset = 1, bool directed = false) {
        if(n == -1) n = this->size() - 1;
        int a, b;
        while(n--) {
            cin >> a >> b;
            Graph::add(a - offset, b - offset, directed);
        }
    }
};
template <typename T> struct WeightedGraph : vector<Edges<T>> {
    using vector<Edges<T>>::vector;
    inline void add(int a, int b, T c, bool directed = false) {
        (*this)[a].emplace_back(b, c);
        if(!directed) (*this)[b].emplace_back(a, c);
    }
    void read(int n = -1, int offset = 1) {
        if(n == -1) n = this->size() - 1;
        int a, b;
        T c;
        while(n--) {
            cin >> a >> b >> c;
            WeightedGraph::add(a - offset, b - offset, c);
        }
    }
};
struct Setup_io {
    Setup_io() {
        ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
        cout << fixed << setprecision(15);
    }
} setup_io;
#pragma endregion

// _________コーディングはここから！！___________

template <typename G = Graph> struct SCC {
    G g;
    Graph rg;
    vector<int> comp, ord;
    vector<bool> used;
    int num; // 連結成分の数

    SCC(G &g) : g(g), rg(g.size()), comp(g.size(), -1), used(g.size()) {
        rep(i, g.size()) for(auto &e : g[i]) rg[e].emplace_back(i);
        ord.reserve(g.size());
        build();
    };
    SCC(int n) : g(n), rg(n), comp(n, -1), used(n) { ord.reserve(n); };
    inline void add(int a, int b) {
        g[a].emplace_back(b);
        rg[b].emplace_back(a);
    }
    int operator[](int k) { return comp[k]; }
    void dfs(int x) {
        if(used[x]) return;
        used[x] = true;
        for(auto &e : g[x])
            if(!used[e]) dfs(e);
        ord.emplace_back(x);
    }
    void rdfs(int x, int cnt) {
        if(comp[x] != -1) return;
        comp[x] = cnt;
        for(int &e : rg[x])
            if(comp[e] == -1) rdfs(e, cnt);
    }
    void build() {
        rep(i, g.size()) dfs(i);
        reverse(all(ord));
        num = 0;
        for(int &i : ord)
            if(comp[i] == -1) { rdfs(i, num), num++; }
    }
    // 強連結成分を潰した DAG を返す
    Graph getGraph() {
        Graph res(num);
        rep(i, g.size()) {
            for(auto &e : g[i]) {
                if(comp[e] == comp[i]) continue;
                res[comp[i]].emplace_back(comp[e]);
            }
        }
        rep(i, g.size()) UNIQUE(res[i]);
        return res;
    }
    // 強連結成分ごとに属する頂点を返す
    vector<vector<int>> belong() {
        vector<vector<int>> res(num);
        rep(i, g.size()) res[comp[i]].emplace_back(i);
        return res;
    }
};

struct TwoSat : SCC<Graph> {
    int n;
    using SCC::SCC;
    TwoSat(int n) : n(n), SCC(n * 2) {}
    // not i = i + n
    inline int rev(int x) { return x >= n ? x - n : x + n; }
    inline int revid(int x) { return rev(id(x)); }
    inline int id(int x) { return x < 0 ? n - x - 1 : x - 1; }
    inline void IF(int x, int y) {
        // x => y
        add(x, y), add(rev(y), rev(x));
    }
    void OR(int x, int y) { IF(rev(id(x)), id(y)); }
    vector<int> solve() {
        build();
        vector<int> res(n);
        rep(i, n) {
            if(comp[i] == comp[rev(i)]) return vector<int>();
            res[i] = comp[i] > comp[rev(i)];
        }
        return res;
    }
    bool can() {
        build();
        rep(i, n) {
            if(comp[i] == comp[rev(i)]) return false;
        }
        return true;
    }
};

const int N = 100;
main() {
    INT(n);
    vi _x(n * 2 + 2), ord(n * 2);
    auto x = _x.begin() + n + 1;
    rep2(i, 1, n) cin >> x[i] >> x[-i];
    rep2(i, 1, n) ord[i * 2 - 2] = i, ord[i * 2 - 1] = -i;
    sort(all(ord), [&](int i, int j) { return x[i] < x[j]; });
    vi y(n * 2);
    rep2(i, 1, n) y[i * 2 - 2] = x[i], y[i * 2 - 1] = x[-i];
    sort(all(y));
    vi _rev(n * 2 + 2);
    auto rev = _rev.begin() + n + 1;
    rep(i, n * 2) rev[ord[i]] = i;
    TwoSat sat(n * 2 + (n * 2 + N - 1) / N * 2);
    int now = n * 2 - 1;
    vi TRUE(n * 2), FALSE(n * 2);
    rep(i, n * 2) {
        if(i % N == 0) now++, TRUE[i] = now;
        sat.add(sat.id(ord[i]), now);
    }
    rep(i, n * 2) {
        if(i % N == 0) now++, FALSE[i] = now;
        sat.add(now, sat.revid(ord[i]));
    }
    auto solve = [&](int d) {
        TwoSat g = sat;
        auto add_edge = [&](auto &&f, int now, int l, int r, int v) -> void {
            if(l <= v and v < r) {
                f(f, now, l, v, n * 2), f(f, now, v + 1, r, n * 2);
                return;
            }
            while(l % N and l < r) {
                g.OR(-now, -ord[l]);
                l++;
            }
            while(l + N <= r) {
                g.add(sat.id(now), FALSE[l]);
                g.add(TRUE[l], sat.revid(now));
                l += N;
            };
            while(l < r) {
                g.OR(-now, -ord[l]);
                l++;
            }
        };
        rep2(i, -n, n) {
            if(!i) continue;
            int pos = x[i];
            int r = lb(y, pos + d);
            add_edge(add_edge, i, rev[i] + 1, r, rev[-i]);
        }
        return g.can();
    };

    int l = 0, r = (1e9 + 1) / (n - 1) + 1;
    while(l < r - 1) {
        int mid = (l + r) >> 1;
        (solve(mid) ? l : r) = mid;
    }
    cout << l << endl;
}


Measured memory_bytes: 135028