#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
#include <cmath>

using namespace std;

struct Point {
  int x, y;
};

int n;
Point v[100];
vector<pair<int, int> > table1[4001];
vector<pair<int, int> > table2[4001];

double GetX(const Point& a, const Point& b, double y) {
  static const double epcilon = 0.000000000001;
  double t = (a.x - b.x) * (y - b.y) / (a.y - b.y) + b.x;
  if(ceil(t) - t < epcilon)
    t = ceil(t);
  if(t - floor(t) < epcilon)
    t = ceil(t);
  return t;
}

void Add(const Point& a, const Point& b) {
  double x1, x2;
  if(a.y < b.y) {
    for(int y = a.y; y < b.y; ++y) {
      x1 = GetX(a, b, y);
      x2 = GetX(a, b, y+1);
      if(a.x > b.x)
	swap(x1, x2);
      table1[y+2000].push_back(make_pair((int)floor(x1), 1));
      table2[y+2000].push_back(make_pair((int)ceil(x2), 1));
    }
  } else {
    for(int y = b.y; y < a.y; ++y) {
      x1 = GetX(a, b, y);
      x2 = GetX(a, b, y+1);
      if(a.x > b.x)
	swap(x1, x2);
      table1[y+2000].push_back(make_pair((int)ceil(x1), -1));
      table2[y+2000].push_back(make_pair((int)floor(x2), -1));
    }
  }
}

int CountT(vector<pair<int, int> >& t) {
  sort(t.begin(), t.end());
  int cnt = 0;
  int state = 0;
  int prev;
  for(vector<pair<int, int> >::iterator p = t.begin(); p != t.end(); ++p) {
    if(state)
      cnt += p->first - prev;
    state += p->second;
    prev = p->first;
  }
  return cnt;
}

int Count() {
  int c1 = 0;
  int c2 = 0;
  for(int i = 0; i < 4001; ++i) {
    c1 += CountT(table1[i]);
    c2 += CountT(table2[i]);
  }
  return max(c1, c2);
}

int main() {
  while(cin >> n && n) {
    for(int i = 0; i < 4001; ++i) {
      table1[i].clear();
      table2[i].clear();
    }
    for(int i = 0; i < n; ++i) {
      cin >> v[i].x >> v[i].y;
      if(i)
	Add(v[i-1], v[i]);
    }
    Add(v[n-1], v[0]);
    cout << Count() << endl;
  }
}