program haromszog;
var x,y:array[1..1500] of double;
    a:array[1..1500,1..1500] of longint;
    n,i,j,k:integer;
    f,g:text;
    d:double;
    db:longint;

begin
        assign(f,'triang.in');reset(f);
        assign(g,'triang.out');rewrite(g);
        readln(f,n);
        for i:=1 to n do begin
                read(f,x[i]);
                readln(f,y[i]);end;

        for i:=1 to n-1 do
                for j:=i+1 to n do begin
                       d:=((x[j]-x[i])*(x[j]-x[i]))+
                          ((y[j]-y[i])*(y[j]-y[i]));
                       a[i,j]:=round(d);
                       end;

        for i:=1 to n-2 do
                for j:=i+1 to n-1 do
                        for k:=j+1 to n do
                                if (a[i,j]=a[i,k]) and (a[i,j]=a[j,k])
                                        then inc(db);

        write(g,db);
        close(f);close(g);
end.