var x, y: array[1..1000] of longint;
    u1, u2: array[1..1000] of boolean;
    n, m, i, t, j, k, f: integer;

begin
 assign(input,'trapez.in');
 reset(input);
 assign(output,'trapez.out');
 rewrite(output);
  readln(n);
  for i:=1 to n do begin read(x[i]); read(y[i]); u1[i]:=false; u2[i]:=false; end;
  t:=0;
  for i:=1 to n-1 do
    for j:=i+1 to n do

      for k:=1 to n-1 do
       if (k<>i) and (k<>j) then
        for f:=k+1 to n do
         if (f<>i) and (f<>j) then
           begin
            if (((x[k]-x[f]=0) and (x[i]-x[j]=0))
               or ((y[k]-y[f]=0) and (y[i]-y[j]=0)) or
                 (((x[k]-x[f]<>0) and (x[i]-x[j]<>0) and (y[k]-y[f]<>0) and (y[i]-y[j]<>0))
                 and ((x[k]-x[f])/(y[k]-y[f])=(x[i]-x[j])/(y[i]-y[j]))))
                 and ( not(u2[k]) or not(u2[f]) or not(u1[k]) or not(u1[k]))
                  then begin
                        inc(t);
                        u1[i]:=true; u2[i]:=true;
                        u2[j]:=true; u2[j]:=true;
                        u2[k]:=true; u2[k]:=true;
                        u2[f]:=true; u2[f]:=true;

                        end;

                        end;
        writeln(t);



 close(input);
 close(output);
end.