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 <bits/stdc++.h>
using namespace std;
typedef struct {
  int x;
  int y;
} mypoint;
int n;
long long tri;
int idx[3100];
mypoint points[3100], ox;
int oxidx;
void findox(void) {
  ox.x = points[0].x;
  ox.y = points[0].y;
  oxidx = 0;
  for (int i = 0; i < (n); ++i)
    if (points[i].x < ox.x) {
      ox.x = points[i].x;
      ox.y = points[i].y;
      oxidx = i;
    } else if (points[i].x == ox.x) {
      if (points[i].y < ox.y) {
        ox.x = points[i].x;
        ox.y = points[i].y;
        oxidx = i;
      }
    }
}
double signed_triangle_area(mypoint *a, mypoint *b, mypoint *c) {
  return (a->x * b->y - a->y * b->x + a->y * c->x - a->x * c->y + b->x * c->y -
          c->x * b->y);
}
bool ccw(mypoint *a, mypoint *b, mypoint *c) {
  return signed_triangle_area(a, b, c) > 0.000001;
}
int smaller_angle(const void *p1, const void *p2) {
  if (ccw(&ox, &points[*(int *)p1], &points[*(int *)p2]))
    return -1;
  else
    return 1;
}
void anglesort(void) {
  for (int i = 0; i < (n); ++i) idx[i] = i;
  qsort(idx, n, sizeof(idx[0]), smaller_angle);
}
void comptri(void) {
  int pre = 0;
  for (int i = (1); i <= (n - 1); ++i)
    if (abs(signed_triangle_area(&ox, &points[idx[i - 1]], &points[idx[i]])) ==
        0) {
      tri++;
      tri += pre;
      pre++;
    } else
      pre = 0;
}
void delox() {
  for (int i = (oxidx); i <= (n - 2); ++i) {
    points[i] = points[i + 1];
  }
  n--;
}
void proc(void) {
  while (n >= 3) {
    findox();
    delox();
    anglesort();
    comptri();
  }
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < (n); ++i) scanf("%d %d", &points[i].x, &points[i].y);
  tri = 0;
  proc();
  printf("%I64d\n", tri);
  return 0;
}
