1 #include<algorithm>
 2 #include<iostream>
 3 #include<iomanip>
 4 #include<cstdlib>
 5 #include<cstring>
 6 #include<vector>
 7 #include<cstdio>
 8 #include<stack>
 9 #include<queue>
10 #include<cmath>
11 #include<ctime>
12 #include<set>
13 #include<map>
14 #define ll long long
15 #define rep(i,a,b) for(register int i=a;i<=b;i++)
16 #define inf 1<<29
17 #define re register
18 using namespace std;
19 #define eps 1e-6
20 const int N=110;
21 struct point{
22     double x,y;
23 }d[2];
24 struct line{
25     double k,b;
26     double l,r,ly,ry;
27 }L[N];
28 int n;
29 inline bool pd(double x,double y,int k) {
30     return (x>=L[k].l&&x<=L[k].r&&y>=L[k].ly&&y<=L[k].ry);
31 }
32 inline bool judge(int i,int j) {
33     if(fabs(L[i].k-L[j].k)<=eps) return 0;
34     if(fabs(L[i].k-0)<=eps&&fabs(L[j].k-0)<=eps) return 0;
35     if(fabs(L[i].k-0)>eps&&fabs(L[j].k-0)>eps) {
36         double x=(L[j].b-L[i].b)/(L[i].k-L[j].k),
37             y=L[i].k*x+L[i].b;
38         if(pd(x,y,i)&&pd(x,y,j)) return 1;
39         else return 0;
40     }
41     if(fabs(L[i].k-0)<=eps) {
42         double x=L[i].l;
43         double y=L[j].k*x+L[j].b;
44         return (y>=L[j].ly&&y<=L[j].ry);
45     }
46     double x=L[j].l;
47     double y=L[i].k*x+L[i].b;
48     return (y>=L[i].ly&&y<=L[i].ry);
49 }
50 int main() {
51     freopen("Y.in","r",stdin);
52     freopen("Y.out","w",stdout);
53     while(scanf("%d",&n)&&n) {
54         for(int i=1;i<=n;i++) {
55             scanf("%lf%lf%lf%lf",&d[0].x,&d[0].y,&d[1].x,&d[1].y);
56             L[i].l=min(d[0].x,d[1].x),L[i].r=max(d[0].x,d[1].x);
57             L[i].ly=min(d[0].y,d[1].y),L[i].ry=max(d[0].y,d[1].y);
58             if(fabs(d[1].x-d[0].x)<=eps)
59                 L[i].k=0;
60             else {
61                 L[i].k=(d[1].y-d[0].y)/(d[1].x-d[0].x);
62                 L[i].b=d[0].y-L[i].k*d[0].x;
63             }
64         }
65         int ans=0;
66         for(int i=1;i<n;i++)
67             for(int j=i+1;j<=n;j++)
68                 if(judge(i,j)) ans++;
69         cout<<ans<<endl;
70     }
71     return 0;
72 }