var a:array[1..2,1..1000]of longint;
    b:array[1..2,1..500000]of real;
    i,n,j,v,p1,p2:longint;
    t1,t2,rs:int64;
    buf:array[1..1 shl 10]of char;

{procedure qsort(st,dr:longint);
  var i,j,t:longint; m:int64; bl:boolean;
  begin
    i:=st; j:=dr; m:=(i+j)div 2;
    repeat
      bl:=true;
      while bl do begin if b[2,i]*b[2,m]<0 then t:=-1 else t:=1; if b[1,i]*b[2,m]*t<b[1,m]*b[2,i]*t then inc(i) else bl:=false end;
      bl:=true;
      while bl do begin if b[2,j]*b[2,m]<0 then t:=-1 else t:=1; if b[1,j]*b[2,m]*t>b[1,m]*b[2,j]*t then dec(j) else bl:=false end;
      if i<=j then begin t:=b[1,i]; b[1,i]:=b[1,j]; b[1,j]:=t; t:=b[2,i]; b[2,i]:=b[2,j]; b[2,j]:=t; inc(i); dec(j); end;
    until i>=j;
    if st<j then qsort(st,j);
    if i<dr then qsort(i,dr);
  end;  }

procedure qsort(i,j:longint);
   var st,dr:longint; t,m:real;
  begin
    m:=b[1,(i+j)div 2]; st:=i; dr:=j;
    repeat
      while b[1,i]<m do inc(i);
      while b[1,j]>m do dec(j);
      if i<=j then begin t:=b[1,i]; b[1,i]:=b[1,j]; b[1,j]:=t; t:=b[2,i]; b[2,i]:=b[2,j]; b[2,j]:=t; inc(i); dec(j); end;
    until i>j;
    if st<j then qsort(st,j);
    if i<dr then qsort(i,dr);
  end;

begin
  assign(input,'trapez.in'); reset(input);
  readln(n);
  for i:=1 to n do readln(a[1,i],a[2,i]);
  v:=0;
  for i:=1 to n-1 do
    for j:=i+1 to n do
      begin
        if {(a[2,i]-a[2,j]<>0) and} (a[1,i]-a[1,j]<>0) then
          begin
            inc(v);
            b[1,v]:=(a[2,i]-a[2,j])/(a[1,i]-a[1,j]);
           { b[2,v]:=a[1,i]-a[1,j];}
          end
        else
          begin
            {if a[2,i]-a[2,j]<>0 then inc(p1)
            else if a[1,i]-a[1,j]<>0 then inc(p2);}
            inc(p1);
          end;
      end;
  qsort(1,v); t1:=0;
  for i:=2 to v do if {b[1,i]*b[2,i-1]=b[1,i-1]*b[2,i]} b[1,i]=b[1,i-1] then inc(t1) else begin rs:=rs+t1*(t1-1)div 2; t1:=0; end;
  rs:=rs+(p1*(p1-1)div 2);
  rs:=rs+(p2*(p2-1)div 2);
  assign(output,'trapez.out'); rewrite(output);
  writeln(rs);
  close(output);
end.