#include <bits/stdc++.h>

//    #include <boost/multiprecision/cpp_int.hpp>
 #define int long long
 #define inf  1000000007
 #define pa pair<int,int>
 #define ll long long
 #define pal pair<double,double>
 #define ppap pair<pa,int>
  #define PI 3.14159265358979323846
  #define paa pair<int,char>
  #define  mp make_pair
  #define  pb push_back
  #define EPS (1e-10)
                                          
//    int dx[8]={0,1,0,-1,1,1,-1,-1};
  //  int dy[8]={1,0,-1,0,-1,1,1,-1};
                                            using namespace std;
                                   			class pa3{
                                            	public:
                                            	int x;
                                   				int y,z;
                                            	pa3(int x=0,int y=0,int z=0):x(x),y(y),z(z) {}
                                            	bool operator < (const pa3 &p) const{
                                            		if(x!=p.x) return x<p.x;
                                            		if(y!=p.y) return y<p.y;
                                            		 return z<p.z;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                   				bool operator > (const pa3 &p) const{
                                            		if(x!=p.x) return x>p.x;
                                            		if(y!=p.y) return y>p.y;
                                            		 return z>p.z;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa3 &p) const{
                                            		return x==p.x && y==p.y && z==p.z;
                                            	}
                                            		bool operator != (const pa3 &p) const{
                                            			return !( x==p.x && y==p.y && z==p.z);
                                            	}
                                            
                                            };
                                            
                                            class pa4{
                                            	public:
                                            	int x;
                                            	int y,z,w;
                                            	pa4(int x=0,int y=0,int z=0,int w=0):x(x),y(y),z(z),w(w) {}
                                            	bool operator < (const pa4 &p) const{
                                            		if(x!=p.x) return x<p.x;
                                            		if(y!=p.y) return y<p.y;
                                            		if(z!=p.z)return z<p.z;
                                            		return w<p.w;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator > (const pa4 &p) const{
                                            		if(x!=p.x) return x>p.x;
                                            		if(y!=p.y) return y>p.y;
                                            		if(z!=p.z)return z>p.z;
                                            		return w>p.w;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa4 &p) const{
                                            		return x==p.x && y==p.y && z==p.z &&w==p.w;
                                            	}
                                            		
                                            
                                            };
                                            class pa2{
                                            	public:
                                            	int x,y;
                                            	pa2(int x=0,int y=0):x(x),y(y) {}
                                            	pa2 operator + (pa2 p) {return pa2(x+p.x,y+p.y);}
                                            	pa2 operator - (pa2 p) {return pa2(x-p.x,y-p.y);}
                                            	bool operator < (const pa2 &p) const{
                                            		return y != p.y ? y<p.y: x<p.x;
                                            	}
                                            	bool operator > (const pa2 &p) const{
                                            		return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa2 &p) const{
                                            		return abs(x-p.x)==0 && abs(y-p.y)==0;
                                            	}
                                            	bool operator != (const pa2 &p) const{
                                            		return !(abs(x-p.x)==0 && abs(y-p.y)==0);
                                            	}
                                            		
                                            
                                            };
                                        

                                            class Point{
                                            	public:
                                            	double x,y;
                                            	Point(double x=0,double y=0):x(x),y(y) {}
                                            	Point operator + (Point p) {return Point(x+p.x,y+p.y);}
                                            	Point operator - (Point p) {return Point(x-p.x,y-p.y);}
                                            	Point operator * (double a) {return Point(x*a,y*a);}
                                            	Point operator / (double a) {return Point(x/a,y/a);}
                                            	double absv() {return sqrt(norm());}
                                            	double norm() {return x*x+y*y;}
                                            	bool operator < (const Point &p) const{
                                            		return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const Point &p) const{
                                            		return fabs(x-p.x)<EPS && fabs(y-p.y)<EPS;
                                            	}
                                            };
                                            typedef Point Vector;
                                     #define pl pair<int,pas>
                                            struct Segment{
                                            Point p1,p2;
                                            };
                                             double dot(Vector a,Vector b){
                                            	return a.x*b.x+a.y*b.y;
                                            }
                                            double cross(Vector a,Vector b){
                                            	return a.x*b.y-a.y*b.x;
                                            }
                                        
                bool parareru(Point a,Point b,Point c,Point d){
                //	if(abs(cross(a-b,d-c))<EPS)cout<<"dd "<<cross(a-b,d-c)<<endl;
                	return abs(cross(a-b,d-c))<EPS;
                }
                double distance_ls_p(Point a, Point b, Point c) {
                  if ( dot(b-a, c-a) < EPS ) return (c-a).absv();
                  if ( dot(a-b, c-b) < EPS ) return (c-b).absv();
                  return abs(cross(b-a, c-a)) / (b-a).absv();
                }
                bool is_intersected_ls(Segment a,Segment b) {
                	if(a.p1==b.p1||a.p2==b.p1||a.p1==b.p2||a.p2==b.p2) return false;
                	if(parareru((a.p2),(a.p1),(a.p1),(b.p2))&&parareru((a.p2),(a.p1),(a.p1),(b.p1))){
                //		cout<<"sss"<<endl;
                		if(dot(a.p1-b.p1,a.p1-b.p2)<EPS) return true;
                		if(dot(a.p2-b.p1,a.p2-b.p2)<EPS) return true;
                		if(dot(a.p1-b.p1,a.p2-b.p1)<EPS) return true;
                		if(dot(a.p1-b.p2,a.p2-b.p2)<EPS) return true;
                		return false;
                	}
                  else return ( cross(a.p2-a.p1, b.p1-a.p1) * cross(a.p2-a.p1, b.p2-a.p1) < EPS ) && ( cross(b.p2-b.p1, a.p1-b.p1) * cross(b.p2-b.p1, a.p2-b.p1) < EPS );
                }
                 
                double segment_dis(Segment a,Segment b){
                	if(is_intersected_ls(a,b))return 0;
                	double r=distance_ls_p(a.p1, a.p2, b.p1);
                	r=min(r,distance_ls_p(a.p1, a.p2, b.p2));
                	r=min(r,distance_ls_p(b.p1, b.p2, a.p2));
                	r=min(r,distance_ls_p(b.p1, b.p2, a.p1));
                	return r;
                }
                Point intersection_ls(Segment a, Segment b) {
                  Point ba = b.p2-b.p1;
                  double d1 = abs(cross(ba, a.p1-b.p1));
                  double d2 = abs(cross(ba, a.p2-b.p1));
                  double t = d1 / (d1 + d2);
                 
                  return a.p1 + (a.p2-a.p1) * t;
                }
                
                                string itos( int i ) {
                                ostringstream s ;
                                s << i ;
                                return s.str() ;
                                }
                                 
                                int gcd(int v,int b){
                                	if(v>b) return gcd(b,v);
                                	if(v==0)return b;
                                	if(v==b) return b;
                                	if(b%v==0) return v;
                                	return gcd(v,b%v);
                                }
                 
                                double distans(double x1,double y1,double x2,double y2){
                                	double rr=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
                                	return sqrt(rr);
                                	
                                }
                                int mod;
ll extgcd(ll a, ll b, ll &x, ll &y) {
    if (b == 0ll) {
        x = 1ll;
        y = 0ll;
        return a;
    }
    ll d = extgcd(b, a%b, y, x);
    y -= a/b * x;
    return d;
}
pa operator+(const pa & l,const pa & r) {   
    return {l.first+r.first,l.second+r.second};                                    
}    
pa operator-(const pa & l,const pa & r) {   
    return {l.first-r.first,l.second-r.second};                                    
} 
                                
                int pr[200010];
                int inv[200010];
                
                int beki(int wa,int rr,int warukazu){
                	if(rr==0) return 1%warukazu;
                	if(rr==1) return wa%warukazu;
                	wa%=warukazu;
                	if(rr%2==1) return ((ll)beki(wa,rr-1,warukazu)*(ll)wa)%warukazu;
                	ll zx=beki(wa,rr/2,warukazu);
                	return (zx*zx)%warukazu;
                }
    double bekid(double w,int r){
    	if(r==0) return 1.0;
    	if(r==1) return w;
    	if(r%2) return bekid(w,r-1)*w;
    	double f=bekid(w,r/2);
    	return f*f;
    }
                
    			int comb(int nn,int rr){
    				int r=pr[nn]*inv[rr];
    				r%=mod;
    				r*=inv[nn-rr];
    				r%=mod;
    				return r;
    			}
                
                void gya(int ert){
                	pr[0]=1;
                	for(int i=1;i<=ert;i++){
                		pr[i]=(pr[i-1]*i)%mod;
                	}
                	inv[ert]=beki(pr[ert],mod-2,mod);
                	
                	for(int i=ert-1;i>=0;i--) inv[i]=inv[i+1]*(i+1)%mod;
                	
                }
                
              //   cin.tie(0);
    		//	ios::sync_with_stdio(false);
    			//priority_queue<pa3,vector<pa3>,greater<pa3>> pq;            
                 //sort(ve.begin(),ve.end(),greater<int>());
    //mt19937(clock_per_sec);
  //  mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count()) ;
	   
       
                               //----------------kokomade tenpure------------

int C;
struct kyouren{
private:
	public:
int V;
	vector<vector<int>> gr,igr;
	vector<int> visit,gro,ban;
	void shoki(int N){
		V=N;
			gr.resize(N,{});
			igr.resize(N,{});
		visit.resize(N,0);
		gro.resize(N,0);
	}
	
	void add_edge(int x,int y){
		// 0<= x,y <N
		gr[x].pb(y);
		igr[y].pb(x);
	}
	
	
	
	void dfs(int i){
		if(visit[i]==0){
			visit[i]=1;
			for(int k=0;k<(int)gr[i].size();k++) dfs(gr[i][k]);
			ban.push_back(i);
		}
	}

	void idfs(int i,int h){
		if(visit[i]==0){
			visit[i]=1;
			gro[i]=h;
			for(int k=0;k<(int)igr[i].size();k++) idfs(igr[i][k],h);
		}
	}

	void shori(){
		for(int i=0;i<V;i++){
			dfs(i);
		}
		for(int i=0;i<V;i++) visit[i]=0;
		for(int i=V-1;i>=0;i--){
			idfs(ban[i],ban[i]);
		}
	}
		bool same(int x,int y){
			return gro[x]==gro[y];
		}
		
		int id(int x){
			return gro[x];
		}

	
	
	void add_edge_p(int st,int a,int b,int k=1,int l=0,int r=2*C){
		if(a<=l && r<=b){
			add_edge(2*C+st,k);
			return;
		}
		if(r<=a || b<=l){
			return ;
		}
		add_edge_p(st,a,b,2*k,l,(l+r)/2);
		
		add_edge_p(st,a,b,2*k+1,(l+r)/2,r);
	}

};


int n;
vector<pa3> ve;

int pos[10100][2];
int id[10100][2];

bool ch(int r){
	kyouren ss;
	
	ss.shoki(4*C);
	for(int i=1;i<2*C;i++){
		ss.add_edge(i,2*i);
		ss.add_edge(i,2*i+1);
	}
	//cout<<r<<endl;
	for(int i=1;i<=n;i++){
		for(int p=0;p<2;p++){
			int w=pos[i][1^p];
				int lef=lower_bound(ve.begin(),ve.end(),(pa3){w-r,-1,-1})-ve.begin();
				int rig=upper_bound(ve.begin(),ve.end(),(pa3){w+r,inf,inf})-ve.begin();
	//		cout<<id[i][p]<<"  "<<lef<<" "<<rig<<endl;
			ss.add_edge_p(id[i][p],lef,id[i][1^p]);
			ss.add_edge_p(id[i][p],id[i][1^p]+1,rig);
			
		}
	}
	ss.shori();
	//cout<<r<<endl;
	for(int i=1;i<=n;i++){
		if(ss.same(2*C+id[i][0],2*C+id[i][1]))return 0;
	}
	return 1;
}

signed main(){

		  cin.tie(0);
	ios::sync_with_stdio(false);
cin>>n;
	C=1024*16;
//	C=16;
	for(int i=1;i<=n;i++){
		int y,yy;
		cin>>y>>yy;
		pos[i][1]=y;
		pos[i][0]=yy;
			ve.pb({y,C+i});
			ve.pb({yy,C-i});
	}
	sort(ve.begin(),ve.end());
	for(int i=0;i<2*n;i++){
		if(ve[i].y<C){
			id[C-ve[i].y][0]=i;
		}
		else if(ve[i].y>C){
			id[ve[i].y-C][1]=i;
		}
	}
	int si=0,ue=inf*100ll,me;
//	cout<<ch(100)<<endl;
//	return 0;
	
	if(!ch(0)){
		cout<<0<<endl;
		return 0;
	}
	
//	cout<<"s"<<endl;
	
	while(ue-si>1){
		me=(ue+si)/2;
		if(ch(me)){
			si=me;
		}
		else ue=me;
	}
	cout<<ue<<endl;
	return 0;
}

Measured memory_bytes: 25600