10
-2 1
2 -2
-1 -2
0 0
2 -1
0 -2
2 2
0 2
-1 -1
1 -2
 40
-8 24
2 -1
1 -18
72 -70
5 -4
-308 436
-19 40
36 -35
-178 265
-1 2
-7 30
-1 0
3 -2
200 -285
17 -16
-35 74
0 -4
-86 106
-1 4
-7 6
0 1
-5 4
-2 3
6 -5
-4 5
181 -262
76 -118
0 0
-7 18
-58 104
-5 6
-6 12
-3 4
1 0
11 -10
-86 130
-3 6
153 -236
-183 270
-33 64
 5
0 -1
0 -2
0 -3
0 -4
0 -5
 10
0 1
-1 -1
1 1
-1 0
1 -1
-2 -1
-2 2
-2 0
0 -2
0 -1
 20
-1 18
-2 5
-5 4
2 -33
9 -18
0 0
11 -22
2 0
-1 2
-4 41
1 6
1 -2
6 -12
0 1
-3 6
3 -6
3 -8
-1 4
2 -5
1 0
 10
2 1
-1 0
-2 -1
-1 1
0 2
2 -2
0 0
-2 -2
0 -2
-2 1
 20
-3 -3
0 4
-3 1
1 1
-1 2
-4 4
3 -1
-3 0
0 2
4 0
2 3
2 4
4 -3
-4 3
-1 1
1 3
-2 4
1 -2
1 -1
3 0
 3
0 0
0 -1
0 1
 10
2 1
-1 1
0 0
-3 1
-2 -3
-1 -2
-1 -1
1 2
3 -2
0 -2
 3
3 3
1 2
1 1
 4
0 0
1 0
2 0
3 0
 9
1 1
1 0
0 1
0 0
-1 0
-1 1
-1 -1
1 -1
0 -1
 7
1 1
-1 -1
1 0
0 1
-1 0
0 -1
0 0

4
 57
 4
 5
 21
 4
 10
 1
 1
 0
 2
 8
 3

#include <iostream>
using namespace std;
#define SIZE 3000

/*struct dot{
	int A,B,C;
};*/

void main()
{
	int x[SIZE], y[SIZE], kol_dot, kol=-1;
	float k1,b1,k2,b2;
	//dot dots[SIZE];

	cin>>kol_dot;
	//for(int i=0;i<kol_dot;i++)
	//	cin>>x[i]>>y[i];

	for(int a=0;a<(kol_dot-1);a++)
		for(int c=a+1;c<kol_dot;c++)
			for(int b=0;b<kol_dot;b++){
				if(((x[a]>x[b] && x[c]<x[b])||(x[a]<x[b] && x[c]>x[b]))&&((y[a]>y[b] && y[c]<y[b])||(y[a]<y[b] && y[c]>y[b]))) {
					k1=(y[c]-y[a]);
					k1=k1/(x[c]-x[a]);
					k2=(y[b]-y[a]);
					k2=k2/(x[b]-x[a]);
					b1=y[a]-k1*x[a];
					b2=y[a]-k2*y[a];
					if(b1==0 || b2==0) {
						b1=y[c]-k1*x[c];
						b2=y[b]-k2*x[b];}
					if(k1==k2 && b1==b2){
						kol++;
						//dots[kol].A=a;
						//dots[kol].B=b;
						//dots[kol].C=c;
					}
				}
				if((x[a]==x[b] && x[c]==x[b] && y[a]<y[b] && y[c]>y[b])||(y[a]==y[b] && y[c]==y[b] && x[a]<x[b] && x[c]>x[b])){
						kol++;
						//dots[kol].A=a;
						//dots[kol].B=b;
						//dots[kol].C=c;
					}
			}
	cout<<(kol+1)<<"\n";
	//for(int i=0;i<=kol;i++)
		//cout<<dots[i].A<<" "<<dots[i].B<<" "<<dots[i].C<<"\n";
}