#include<bits/stdc++.h>

using namespace std;

struct vec{
  int x,y;

  vec(int X=0,int Y=0){
    x=X,y=Y;
  }

  friend vec operator - (const vec &x,const vec &y){
    return vec(x.x-y.x,x.y-y.y);
  }

  friend bool operator == (const vec &x,const vec &y){
    return x.x==y.x&&x.y==y.y;
  }
};

int dis(const vec &a,const vec &b){
  return (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y);
}

int triArea(const vec &a,const vec &b,const vec &c){
  return abs(a.x*b.y+b.x*c.y+c.x*a.y-a.x*c.y-b.x*a.y-c.x*b.y);
}

int main(){

  int n;
  cin>>n;
  vector<vec> pt(n+1);
  int maxx=0,maxy=0;
  for(int i=1; i<=n; i++){
    cin>>pt[i].x>>pt[i].y;
    maxx=max(maxx,pt[i].x);
    maxy=max(maxy,pt[i].y);
  }

  int SUM=0;
  for(int i=3; i<=n; i++){
    SUM=SUM+triArea(pt[i],pt[i-1],pt[1]);
  }

  auto chk=[&](int x,int y)->bool{
    int S=0;
    for(int i=2; i<=n; i++){
      S+=triArea(vec(x,y),pt[i],pt[i-1]);
    }
    S+=triArea(vec(x,y),pt[n],pt[1]);
    return S==SUM;
  };

  auto square=[&](const vector<vec> &P)->bool{
    if(P[0]==P[1]) return 0;
    int len=dis(P.back(),P[0]);
    for(int i=1; i<4; i++){
      if(dis(P[i],P[i-1])!=len) return 0;
    }
    for(int i=0; i<4; i++) if((P[(i+2)%4].y-P[(i+1)%4].y)*(P[(i+1)%4].y-P[i].y)+(P[(i+2)%4].x-P[(i+1)%4].x)*(P[(i+1)%4].x-P[i].x)!=0) return 0;
    return 1;
  };

  int cc=0;
  int ans=0;
  for(int x1=0; x1<=maxx; x1++)
  for(int y1=0; y1<=maxy; y1++){
    if(!chk(x1,y1)) continue;
    for(int x2=0; x2<=maxx; x2++)
    for(int y2=0; y2<=maxy; y2++){
      if(!chk(x2,y2)) continue;
      for(int x3=0; x3<=maxx; x3++)
      for(int y3=0; y3<=maxy; y3++){
        if(!chk(x3,y3)) continue;
        if(dis(vec(x1,y1),vec(x2,y2))!=dis(vec(x2,y2),vec(x3,y3))) continue;
        for(int x4=0; x4<=maxx; x4++)
        for(int y4=0; y4<=maxy; y4++){
          if(!chk(x4,y4)) continue;
          cc++;
          if(square({vec(x1,y1),vec(x2,y2),vec(x3,y3),vec(x4,y4)})){
            ans++;
            //cerr<<x1<<' '<<y1<<' '<<x2<<' '<<y2<<' '<<x3<<' '<<y3<<' '<<x4<<' '<<y4<<endl;
          }
        }
      }
    }
  }

  cout<<ans/8<<endl;
  //cerr<<cc<<endl;

  return 0;
}
/*

4
0 0
0 10
10 10
10 0

*/