#include<bits/stdc++.h>
using namespace std;
const int N=15;
const double eps=1e-9;
int ss[N<<2];
double ang[N<<2];
struct point{
	double x,y;
}a[N],s[N<<2],sx,sy;
pair<point,point>p[N<<2],q[N<<2],pp[N<<2];
inline bool operator==(point a,point b){
	return fabs(a.x-b.x)<eps&&fabs(a.y-b.y)<eps;
}
inline point operator+(point a,point b){
	return {a.x+b.x,a.y+b.y};
}
inline point operator-(point a,point b){
	return {a.x-b.x,a.y-b.y};
}
inline point operator*(point a,double b){
	return {a.x*b,a.y*b};
}
inline point operator/(point a,double b){
	return {a.x/b,a.y/b};
}
inline double operator^(point a,point b){
	return a.x*b.y-a.y*b.x;
}
inline double angle(pair<point,point>a){
	return atan2(a.second.y-a.first.y,a.second.x-a.first.x);
}
inline point intersect(pair<point,point>a,pair<point,point>b){
	return a.first+(a.second-a.first)/(((a.second-b.first)^(b.second-b.first))+((b.second-b.first)^(a.first-b.first)))*((b.second-b.first)^(a.first-b.first));
}
inline double area(point *q,int n){
	double ans=0;
	for(int i=2;i<=n-1;i++){
		ans+=((q[i]-q[1])^(q[i+1]-q[1]));
	}
	return ans/2;
}
int op;
inline bool check(pair<point,point>a,pair<point,point>b,pair<point,point>c){
	point s=intersect(b,c);
	if(op){
		return ((a.second-s)^(a.first-s))>=-eps;
	}
	return ((a.second-s)^(a.first-s))>eps;
}
inline int Half_Plane_Intersection(pair<point,point> *p,pair<point,point> *q,int n){
	int cnt=0,front=1,back=2;
	static pair<point,point>s[N<<2],d[N<<2],tmp[N<<2];
	for(int i=1;i<=n;i++){
		tmp[i]=p[i];
	}
	s[++cnt]=p[1];
	for(int i=2;i<=n;i++){
		if(fabs(angle(p[i])-angle(p[i-1]))>eps){
			s[++cnt]=p[i];
		}
	}
	d[1]=s[1];
	d[2]=s[2];
	for(int i=3;i<=cnt;i++){
		while(front<back&&check(s[i],d[back],d[back-1])){
			back--;
		}
		while(front<back&&check(s[i],d[front],d[front+1])){
			front++;
		}
		d[++back]=s[i];
	}
	while(front<back&&check(d[front],d[back],d[back-1])){
		back--;
	}
	while(front<back&&check(d[back],d[front],d[front+1])){
		front++;
	}
	cnt=0;
	for(int i=front;i<=back;i++){
		q[++cnt]=d[i];
	}
	for(int i=1;i<=n;i++){
		p[i]=tmp[i];
	}
	return cnt;
}
inline bool check1(point a,pair<point,point> *p,int n){
	for(int i=1;i<=n;i++){
		if(((p[i].second-a)^(p[i].first-a))>eps){
			return 0;
		}
	}
	return 1;
}
inline int f(int a,int b,int c,int n){
	if(a>=c||b>=c){
		return f(a%c,b%c,c,n)+a/c*n*(n+1)/2+(n+1)*(b/c);
	}
	int m=(a*n+b)/c;
	if(m==0){
		return 0;
	}
	return n*m-f(c,c-b-1,a,m-1);
}
inline int solve(point p,int dx,int dy,int l,int r){
	int del,d=abs(__gcd(dx,dy)),ans=0;
	dx/=d;
	dy/=d;
	for(int i=l;i<=r;i++){
		ans+=p.y+(i-p.x)*dy/dx+1;
	}
	return ans;
//	return f(dy,dx*p.y-p.x*dy,dx,r)-f(dy,dx*p.y-p.x*dy,dx,l-1)-del*(r-l+1)+(r-l+1);
}
inline int get(point p,int dx,int dy,int l,int r){
	dx/=__gcd(dx,dy);
	dx=abs(dx);
	return floor((r-p.x)/dx)-floor((l-1-p.x)/dx);
}
inline bool isint(double x){
	return fabs(x-floor(x))<eps||fabs(x-ceil(x))<eps;
}
int main(){
	int n,maxx=0,cnt,cntt,cntp;
	long long ans=0;
	scanf("%d",&n);
	for(int i=1;i<=n;i++){
		scanf("%lf%lf",&a[i].x,&a[i].y);
		maxx=max({(double)maxx,a[i].x,a[i].y});
	}
	a[n+1]=a[1];
	reverse(a+1,a+n+2);
	for(int i=0;i<=maxx;i++){
		for(int j=1;j<=maxx-i;j++){
			cntp=0;
			for(int k=1;k<=n;k++){
				p[++cntp]={a[k],a[k+1]};
				p[++cntp]={a[k]+(point){-i,-j},a[k+1]+(point){-i,-j}};
				p[++cntp]={a[k]+(point){-i-j,i-j},a[k+1]+(point){-i-j,i-j}};
				p[++cntp]={a[k]+(point){-j,i},a[k+1]+(point){-j,i}};
			}
			for(int i=1;i<=cntp;i++){
				ang[i]=angle(p[i]);
				ss[i]=i;
				pp[i]=p[i];
			}
			sort(ss+1,ss+cntp+1,[](int a,int b){
				if(fabs(ang[a]-ang[b])>eps){
					return ang[a]<ang[b];
				}
				return ((p[a].second-p[a].first)^(p[b].first-p[a].first))<0;
			});
			for(int i=1;i<=cntp;i++){
				p[i]=pp[ss[i]];
			}
			op=0;
			cnt=Half_Plane_Intersection(p,q,cntp);
			cntt=1;
			s[1]=intersect(q[cnt],q[1]);
			for(int k=1;k<=cnt-1;k++){
				s[++cntt]=intersect(q[k],q[k+1]);
				if(s[cntt]==s[cntt-1]){
					cntt--;
				}
			}
			while(cntt!=1&&s[cntt]==s[1]){
				cntt--;
			}
			s[cntt+1]=s[1];
			if(cntt==2&&s[1]==s[2]){
				cntt=1;
			}
			int fl=0;
			for(int k=1;k<=cntt;k++){
				if(isinf(s[k].x)||isnan(s[k].x)||!check1(s[k],p,cntp)){
					fl=1;
				}
			}
			if(fl){
				for(int k=1;k<=cntt;k++){
					if(!(isinf(s[k].x)||isnan(s[k].x)||!check1(s[k],p,cntp))&&isint(s[k].x)&&isint(s[k].y)){
						ans++;
					}
				}
				continue;
			}
			if(cntt==1){
				if(isint(s[1].x)&&isint(s[1].y)){
					ans++;
				}
				continue;
			}
			else if(cntt==2){
				cnt=Half_Plane_Intersection(p,q,cntp);
				cntt=1;
				for(int k=1;k<=cnt-1;k++){
					s[++cntt]=intersect(q[k],q[k+1]);
				}
				s[cntt+1]=s[1]=intersect(q[cnt],q[1]);
				goto lass;
			}
			op=1;
			cnt=Half_Plane_Intersection(p,q,cntp);
			cntt=1;
			for(int k=1;k<=cnt-1;k++){
				s[++cntt]=intersect(q[k],q[k+1]);
			}
			s[cntt+1]=s[1]=intersect(q[cnt],q[1]);
			if(cntt==2&&s[1]==s[2]){
				cntt=1;
			}
			lass:;
			int las=ans;
			q[0]=q[cnt];
			q[cnt+1]=q[1];
			for(int k=1;k<=cnt;k++){
				sx=s[k];
				sy=s[k+1];
				if(q[k].first.x==q[k].second.x){
					if(q[k].first.y>q[k].second.y){
						ans+=floor(sx.y+eps)+1;
					}
					else{
						ans-=floor(sx.y-eps)+1;
					}
				}
				else{
					if(q[k].first.x<q[k].second.x){
						ans-=solve(q[k].first,q[k].second.x-q[k].first.x,q[k].second.y-q[k].first.y,ceil(sx.x-eps),floor(sy.x-eps));
						ans+=get(q[k].first,q[k].second.x-q[k].first.x,q[k].second.y-q[k].first.y,ceil(sx.x-eps),floor(sy.x-eps));
						if(q[k+1].first.x>q[k+1].second.x){
							if(isint(s[k+1].x)){
								ans-=floor(s[k+1].y-eps)+1;
							}
						}
						if(q[k-1].first.x>q[k-1].second.x){
							if(isint(s[k].x)){
								ans+=floor(s[k].y-eps)+1+isint(s[k].y);
							}
						}
					}
					else{
						ans+=solve(q[k].first,q[k].first.x-q[k].second.x,q[k].first.y-q[k].second.y,ceil(sy.x+eps),floor(sx.x+eps));
					}
				}
			}
//			cerr<<i<<" "<<j<<" "<<ans-las<<"\n";
		}
	}
	printf("%lld",ans);
}