#include <cstdio>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <algorithm>
#include <iostream>
#include <cstring>
#include <string>
#include <cassert>
#include <cmath>
#include <cstdlib>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int,int> PII;

#define pb push_back
#define fi first
#define se second

struct Line
{
	int x1, x2, y1, y2;
	ld k;
};

int main()
{
	while(1)
	{
		int n;
		scanf("%d", &n);
		if(n==0) break;
		vector<PII> points;
		int a, b;
		for(int i = 0; i < n; i++)
		{
			scanf("%d %d", &a, &b);
			points.pb(make_pair(a,b));
		}
		vector<Line> lines;
		for(int i = 0; i < n; i++)
		{
			Line l;
			l.x1 = points[i].fi; l.y1 = points[i].se;
			l.x2 = points[(i+1)%n].fi; 	l.y2 = points[(i+1)%n].se;
			if(l.y1==l.y2) continue;
			if(l.y1 > l.y2)
			{
				swap(l.y1,l.y2);
				swap(l.x1,l.x2);
			}
			l.k = ((ld)l.x2-(ld)l.x1)/((ld)l.y2-(ld)l.y1);
			lines.pb(l);
		}
		int co = 0;
		for(int r = -110; r < 110; r++)
		{
			vector<pair<ld, ld> > us;
			for(int i = 0; i < lines.size(); i++)
			{
				if(lines[i].y2<=r || lines[i].y1 > r) continue;
				pair<ld, ld> p;
				p.fi = lines[i].x1 + lines[i].k*(r-lines[i].y1);
				p.se = lines[i].x1 + lines[i].k*(r+1-lines[i].y1);
				us.pb(p);
			}
			sort(us.begin(), us.end());
			for(int i = 0; i+1 < us.size(); i+=2)
			{
				int zu = ceil(max(us[i].se, us[i].fi));
				int ku = floor(min(us[i+1].se, us[i+1].fi));
				if(ku>zu) co+=ku-zu;
			}
		}
		printf("%d\n", co);
	}
	return 0;
}