#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
#define il inline
#define cn const 
typedef double db;
const db eps=1e-8,V=3003;
il int dcmp(cn db &x){return x>eps?1:x<-eps?-1:0;}
struct Point
{
    db x,y;
    void In(){cin>>x>>y;x+=1001;y+=1001;}
    void Out(){cout<<x<<" "<<y<<endl;}
};
il bool operator ==(Point A,Point B){return !dcmp(A.x-B.x)&&!dcmp(A.y-B.y);}
typedef Point Vec;
il Vec operator +(cn Vec &A,cn Vec &B){return {A.x+B.x,A.y+B.y};}
il Vec operator -(cn Vec &A,cn Vec &B){return {A.x-B.x,A.y-B.y};}
il Vec operator *(cn Vec &A,cn db &d){return {A.x*d,A.y*d};}
il db Cro(cn Vec &A,cn Vec &B){return A.x*B.y-A.y*B.x;}
il db Dot(cn Vec &A,cn Vec &B){return A.x*B.x+A.y*B.y;}
il Point Cross_LL(cn Point &a,cn Point &b,cn Point &c,cn Point &d)
{
    Vec x=b-a,y=d-c,z=a-c;
    return a+x*(Cro(y,z)/Cro(x,y));
}
il bool Pan(cn Point &a,cn Point &b,cn Point &c,cn Point &d)
{
    return dcmp(Cro(b-a,c-a))*dcmp(Cro(b-a,d-a))<0&&dcmp(Cro(d-c,a-c))*dcmp(Cro(d-c,b-c))<0;
}
il bool On(cn Point &p,cn Point &a,cn Point &b){return a.x<=p.x&&p.x<=b.x&&a.y<=p.y&&p.y<=b.y;}
il db Atan(Vec a){return atan2(a.y,a.x);}
struct Line
{
    Point a,b;db arg;
    il void Init(cn Point &_a,cn Point &_b){a=_a;b=_b;arg=Atan(b-a);}
    il void Init(db _a,db _b,db _c,db _d){a={_a,_b};b={_c,_d};arg=Atan(b-a);}
    void Out(){cout<<a.x<<" "<<a.y<<" "<<b.x<<" "<<b.y<<endl;}
}Q[23];
il bool operator ==(cn Line &A,cn Line &B){return A.a==B.a&&A.b==B.b;}
il Point Cross(cn Line &L1,cn Line &L2){return Cross_LL(L1.a,L1.b,L2.a,L2.b);}
il bool Chk(cn Line &L,cn Point &a){return dcmp(Cro(a-L.a,L.b-L.a))>0;}
il bool Cmp(cn Line &L1,cn Line &L2)
{
	if(dcmp(L1.arg-L2.arg)!=0)return L1.arg<L2.arg;
	return dcmp(Cro(L2.a-L1.a,L1.b-L1.a))>0;
}
il int Halfcut(Line *L,int n)
{
	sort(L+1,L+n+1,Cmp);int m=n,h=1,t=0;n=0;
    for(int i=1;i<=m;i++)if(i==1||dcmp(L[i].arg-L[i-1].arg))L[++n]=L[i];
    for(int i=1;i<=n;i++)
	{
        while(h<t&&Chk(L[i],Cross(Q[t],Q[t-1])))t--;
        while(h<t&&Chk(L[i],Cross(Q[h],Q[h+1])))h++;
        Q[++t]=L[i];
    }
    while(h<t&&Chk(Q[h],Cross(Q[t],Q[t-1])))t--;
    while(h<t&&Chk(Q[t],Cross(Q[h],Q[h+1])))h++;
	for(int i=h;i<=t;i++)L[i-h+1]=Q[i];
	return t-h+1;
}
il ll F(ll a,ll b,ll c,ll n)
{
    if(!a)return b/c*(n+1);
    if(a>=c||b>=c)return a/c*n*(n+1)/2+b/c*(n+1)+F(a%c,b%c,c,n);
    return (a*n+b)/c*n-F(c,c-b-1,a,(a*n+b)/c-1);
}
il ll Sol(ll a,ll b,ll c,ll n)
{
	ll s=0;
	if(b<0)s+=(-b+c-1)/c*(n+1),b=(b%c+c)%c;
	if(a<0)s+=(-a+c-1)/c*n*(n+1)/2,a=(a%c+c)%c;
	return F(a,b,c,n)-s;
}
il bool Ok(cn Point &a,cn Point &b,cn Point &c,cn Point &d)
{
	return On(a,c,d)||On(b,c,d);
}
const int N=23;
int n,m;
ll ans=0;
Point p[N];
Line L[N],c[N],d[N];
il bool In(cn Point &v)
{
	for(int i=1;i<=n;i++)if(dcmp(Cro(p[i]-v,p[i+1]-v))<=0)return 0;
	return 1;
}
il ll Calc(Point a,Point b,int l,int r,int op)
{
	if(op==0)a.y-=0.0001,b.y-=0.0001;
	if(a.x>b.x)swap(a,b);
	db dt=b.x-a.x,k=b.y-a.y,w=a.y*dt-a.x*k;
    dt*=2000,k*=2000,w*=2000;
	return Sol(k,w+k*l,dt,r-l);
}
signed main()
{
	cin>>n;
	for(int i=1;i<=n;i++)p[i].In();
	reverse(p+2,p+n+1);p[n+1]=p[1];
	for(int i=1;i<=n;i++)L[i].Init(p[i],p[i+1]);
	for(db x=1000;x<=V;x+=0.5)for(db y=dcmp(x-floor(x))*0.5+1000;y<=V;y+=1.0)if(In({x,y}))
	{
		Point v={x,y};m=0;
		for(int i=1;i<=n;i++)
		{
			Point kx=p[i],ky=p[i+1];
		    if(Ok(kx,ky,v,{V,V})||Pan(kx,ky,{V,V},v))
		    L[++m].Init(kx,ky);
		    if(Ok(kx,ky,{0,0},v)||Pan(kx,ky,{0,0},v))
			L[++m].Init(v*2-kx,v*2-ky);
		    if(Ok(kx,ky,{0,y},{x,V})||Pan(kx,ky,{0,V},v))
		    L[++m].Init(x+kx.y-y,y+x-kx.x,x+ky.y-y,y+x-ky.x);
		    if(Ok(kx,ky,{x,0},{V,y})||Pan(kx,ky,{V,0},v))
		    L[++m].Init(x+y-kx.y,y+kx.x-x,x+y-ky.y,y+ky.x-x);
		}
		L[++m].Init(v,{V,y});L[++m].Init({x,V},v);Line las=L[m];
		m=Halfcut(L,m);L[0]=L[m];L[m+1]=L[1];
		int C=0,D=0,st=0,dst=ceil(x+eps),ded=0,cst=0,ced=dst;
		for(int i=1;i<=m;i++)if(L[i]==las){st=i;break;}
		for(int i=st==m?1:st+1;i!=st;i=i==m?1:i+1)if(L[i].b.x!=L[i].a.x)
		{
			if(L[i].b.x>L[i].a.x)d[++D]=L[i];
			else 
			{
			    c[++C]=L[i];
			    if(C==1)cst=ded=floor(Cross(L[i],L[i-1]).x);
			}
		}
		for(int i=1;i<=D;i++)
		{
			int l=dst,r=i==D?ded:floor(Cross(d[i],d[i+1]).x);
			if(l<=r)ans-=Calc(d[i].a,d[i].b,l,r,0),dst=r+1;
		}
		for(int i=1;i<=C;i++)
		{
			int r=cst,l=i==C?ced:ceil(Cross(c[i],c[i+1]).x+eps);
			if(l<=r)ans+=Calc(c[i].a,c[i].b,l,r,1),cst=l-1;
		}
	}
	cout<<ans;
}