#include<cstdio>

 #include<algorithm>

 #define Rint register int

 using namespace std;

 typedef long long LL;

 const int N = ;

 struct Point {

     LL x, y;

     inline Point(LL _x = , LL _y = ): x(_x), y(_y){}

     inline Point operator - (const Point &o) const {return Point(x - o.x, y - o.y);}

     inline LL operator * (const Point &o) const {return x * o.y - y * o.x;}

     inline bool operator < (const Point &o) const {return x < o.x || x == o.x && y > o.y;}

 } p[N], q[N], stk[N];

 int n, m, top;

 int main(){

     scanf("%d", &n);

     for(Rint i = ;i <= n;i ++){

         scanf("%I64d %I64d", &p[i].x, &p[i].y);

         p[i].y -= p[i].x * p[i].x;

     }

     sort(p + , p + n + );

     q[m = ] = p[];

     for(Rint i = ;i <= n;i ++) if(p[i].x != p[i - ].x) q[++ m] = p[i];

     for(Rint i = ;i <= m;i ++){

         while(top >  && (stk[top] - stk[top - ]) * (q[i] - stk[top - ]) >= ) -- top;

         stk[++ top] = q[i];

     }

     printf("%d\n", top - );

 } // nantf tai qiang le!