#include <iostream>
#include <fstream>
#include <deque>
#include <utility>
#include <algorithm>
#include <cmath>
#include <climits>
using namespace std;

#define EPSILON (1e-7)

class point {
public:
  int x, y;
  point();
  point(int &_x, int &_y);
  point(const point &_p);
};
point::point(int &_x, int &_y){ x = _x; y = _y; }
point::point(const point &_p) { x = _p.x; y = _p.y; }
bool operator<(const pair<int, int> &x, const pair<int, int> &y)
{
  if (x.second == INT_MAX && y.second == INT_MAX) {
    return (x.first  <  y.first);
  }
  if (x.second == INT_MAX) {
    return (x.first  <= y.first);
  }
  if (y.second == INT_MAX) {
    return (x.second <  y.first);
  }
  if (x.second < y.second) return true;
  if (x.second > y.second) return false;
  if (x.first  < y.first ) return true;
  if (x.first  > y.first ) return false;
  return false;
}

deque< pair<int, int> > online[4100];

/* 
   Calculate intersection point
   between line-segment(p1 - p2) & line(y = Y)
*/
double cross(point p1, point p2, int Y)
{
  return
    ((double)(p2.x - p1.x) / (double)(p2.y - p1.y)) *
    (double)(Y - p2.y) +
    (double)p2.x;
}

int main()
{
  int n, x, y, miny, maxy;
  deque<point> p;
  //  ifstream cin("area.txt");

  while (1) {
    p.clear();
    for (int i = 0; i < 4100; i++) { online[i].clear(); }
    cin >> n; if (n == 0) { break; }

    miny = 2010; maxy = -2010;
    for (int i = 0; i < n; i++) {
      cin >> x >> y;
      if (miny > y) { miny = y; }
      if (maxy < y) { maxy = y; }
      p.push_back(point(x, y));
    }
    p.push_back(p.front());

    // Trace line
    for (deque<point>::iterator i = p.begin(); i+1 != p.end(); i++) {
      deque<point>::iterator j = i+1;
      for (int y = (i->y < j->y ? i->y : j->y);
           y < (i->y > j->y ? i->y : j->y); y++) {
        double dx1 = cross(*i, *j, y);
        double dx2 = cross(*i, *j, y+1);
        if (fabs(dx2 - dx1) < EPSILON) {
          online[y+2050].push_back(make_pair((int)floor(dx1), INT_MAX));
        }
        else {
          if (dx1 > dx2) { double tmp = dx1; dx1 = dx2; dx2 = tmp; }
          int x1 = (int)floor(dx1);
          int x2 =
            (dx2 - floor(dx2) < EPSILON ? (int)floor(dx2)-1 : (int)floor(dx2));
          online[y+2050].push_back(make_pair(x1, x2));
        }
      }
    }

    for (int y = miny-1; y <= maxy+1; y++) {
      sort(online[y+2050].begin(), online[y+2050].end());
      for (deque< pair<int, int> >::iterator i = online[y+2050].begin();
           i != online[y+2050].end();
           i +=2 ) {
        deque< pair<int, int> >::iterator j = i+1;
/*
cout << "(" << i->first << "," << i->second << ")-";
cout << "(" << j->first << "," << j->second << ")  ";
*/
        if (i->second == INT_MAX) { i->second = i->first; }
        if (j->second == INT_MAX) { j->first--; j->second = j->first; }
      }
/*
cout << endl;
*/
    }
    
    unsigned int area = 0;
    for (int y = miny-1; y <= maxy+1; y++) {
      for (deque< pair<int, int> >::iterator i = online[y+2050].begin();
           i != online[y+2050].end();
           i +=2 ) {
        deque< pair<int, int> >::iterator j = i+1;
/*
cout << "(" << i->first << "," << i->second << ")-";
cout << "(" << j->first << "," << j->second << ")  ";
*/
        if (i != online[y+2050].begin() && (j-2)->second >= i->first) {
          area += j->second - (j-2)->second;
        }
        else {
          area += j->second - i->first + 1;
        }
      }
/*
cout << endl;
*/
    }
    cout << area << endl;
  }
  return 0;
}