#include <fstream>
#include <algorithm>

using namespace std;

ifstream f("patrate3.in");
ofstream g("patrate3.out");

int n,i,sol,j,st,dr,mid,ok,semn;

int x1,x2,x3,x4,yy1,yy2,y3,y4,xg,yg,x;

struct point {
    int x;
    int y;
} v[1005];

char s[20];

bool cmp(const point &a, const point &b) {
    if(a.x==b.x)
        return a.y<b.y;
    return a.x<b.x;
}

int main() {
    f>>n;
    for(j=1;j<=n;j++) {
        f>>s;
        semn=1;x=0;
        if(s[0]=='-')
            semn=-1,x=1;
        for(i=x;s[i]!=0;i++)
            if(s[i]!='.') {
                v[j].x=v[j].x*10+(s[i]-'0')*1.0;
            }
        v[j].x*=2*semn;
        f>>s;
        semn=1;x=0;
        if(s[0]=='-')
            semn=-1,x=1;
        for(i=x;s[i]!=0;i++)
            if(s[i]!='.') {
                v[j].y=v[j].y*10+(s[i]-'0')*1.0;
            }
        v[j].y*=2*semn;
    }
    sort(v+1,v+n+1,cmp);
    sol=0;
    for(i=1;i<n;i++)
        for(j=i+1;j<=n;j++) {
            x1=v[i].x;yy1=v[i].y;
            x3=v[j].x;y3=v[j].y;
            xg=(x1+x3);yg=(yy1+y3);
            xg/=2;yg/=2;
            x2=xg-(y3-yg);yy2=yg+(xg-x1);
            x4=xg+(y3-yg);y4=yg-(xg-x1);
            st=1;dr=n;ok=1;
            while(st<=dr) {
                mid=st+(dr-st)/2;
                if(v[mid].x>x2)
                    dr=mid-1;
                else
                    if(v[mid].x<x2)
                        st=mid+1;
                    else
                        if(v[mid].y>yy2)
                            dr=mid-1;
                        else
                            st=mid+1;
            }
            if(v[dr].x!=x2 || v[dr].y!=yy2 || yy2!=int(yy2) || x2!=int(x2))
                ok=0;
            st=1;dr=n;
            while(st<=dr) {
                mid=st+(dr-st)/2;
                if(v[mid].x>x4)
                    dr=mid-1;
                else
                    if(v[mid].x<x4)
                        st=mid+1;
                    else
                        if(v[mid].y>y4)
                            dr=mid-1;
                        else
                            st=mid+1;
            }
            if(v[dr].x!=x4 || v[dr].y!=y4 || y4!=int(y4) || x4!=int(x4))
                ok=0;
            if(ok)
                sol++;
        }
    g<<sol/2<<"\n";
    return 0;
}