#include<map>
#include<set>
#include<queue>
#include<deque>
#include<cmath>
#include<ctime>
#include<bitset>
#include<vector>
#include<cstdio>
#include<string>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<unordered_map>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef unsigned int uint;
typedef unsigned long long ull;
#define mkp make_pair
#define lb lower_bound
#define ub upper_bound
#define eb emplace_back
#define fs fflush(stdout)
#define ump unordered_map
#define pq priority_queue
#define clz __builtin_clz
#define ctz __builtin_ctz
#define space putchar(' ')
#define enter putchar('\n')
#define sz(x) (int)x.size()
#define np next_permutation
#define clzl __builtin_clzll
#define par __builtin_parity
#define ctzl __builtin_ctzll
#define ppc __builtin_popcount
#define parl __builtin_parityll
#define all(x) x.begin(),x.end()
#define ppcl __builtin_popcountll
#define ms(x,y) memset(x,y,sizeof(x))
#define debug(x) cerr<<#x<<"= "<<(x)<<'\n'
template<class T> inline T &read(T &x){
	x=0;int f=1;char ch=getchar();
	while(ch<48||ch>57){if(ch=='-') f=-f;ch=getchar();}
	while(ch>=48&&ch<=57) x=(x<<1)+(x<<3)+(ch^48),ch=getchar();
	return x*=f;
}
template<class T> inline void print(T x){
	static char buf[40];static int cnt=0;
	if(x<0) putchar(45),x=-x;
	do buf[++cnt]=x%10^48;while(x/=10);
	do putchar(buf[cnt--]);while(cnt);
}
#define mod 998244353
#define inf 0x3f3f3f3f
#define fpi freopen("","r",stdin)
#define fpo freopen("","w",stdout)
bool vis[200005];
struct point{int x,y;bool operator <(const point &a)const{if(x==a.x) return y<a.y;return x<a.x;}}p[200005];
inline bool isline(point a,point b,point c){return (ll)(b.x-a.x)*(c.y-b.y)==(ll)(c.x-b.x)*(b.y-a.y);}
void solve(int n){
	int now1=1,now2=2,now3=3,ans=n,i;
	for(i=1;i<=n;i++) vis[i]=0;
	for(i=1;i<=n;i++) read(p[i].x),read(p[i].y);
	sort(p+1,p+n+1);
	while(1){
		while(now3<=n&&isline(p[now1],p[now2],p[now3])) now3++;
		if(now3>n){print(ans),enter;return ;}ans-=3;
		vis[now1]=vis[now2]=vis[now3]=1;
		while(now1<=n&&vis[now1]) now1++;now2=now1+1;
		while(now2<=n&&vis[now2]) now2++;now3=now2+1;
		while(now3<=n&&vis[now3]) now3++;
	}
}
int main(){
	int n;while(cin>>n) solve(n);
	return 0;
}