var i,j,k,l,n,r,aux,ii,jj:longint;
    x,y:array[1..4]of longint;
    a:array[1..1000,1..2]of longint;
    f,g:text;

begin
assign(f,'trapez.in');
reset(f);
readln(f,n);
for i:=1 to n do readln(f,a[i,1],a[i,2]);
for i:=1 to n-3 do
   for j:=i+1 to n-2 do
      for k:=j+1 to n-1 do
         for l:=k+1 to n do begin
            x[1]:=a[i,1];
            x[2]:=a[j,1];
            x[3]:=a[k,1];
            x[4]:=a[l,1];
            y[1]:=a[i,2];
            y[2]:=a[j,2];
            y[3]:=a[k,2];
            y[4]:=a[l,2];
            for ii:=1 to 3 do
               for jj:=ii+1 to 4 do
                  if y[ii]<y[jj] then begin
                                      aux:=y[ii];
                                      y[ii]:=y[jj];
                                      y[jj]:=aux;
                                      aux:=x[ii];
                                      x[ii]:=x[jj];
                                      x[jj]:=aux;
                                      end;
            if x[1]<x[2] then if x[3]<x[4] then begin
                                                aux:=y[3];
                                                y[3]:=y[4];
                                                y[4]:=aux;
                                                aux:=x[3];
                                                x[3]:=x[4];
                                                x[4]:=aux;
                                                end
                                           else begin end
                         else if x[3]>x[4] then begin
                                                aux:=y[3];
                                                y[3]:=y[4];
                                                y[4]:=aux;
                                                aux:=x[3];
                                                x[3]:=x[4];
                                                x[4]:=aux;
                                                end;
            if y[2]-y[1]<>0 then if y[3]-y[4]<>0 then if abs((x[2]-x[1])/(y[2]-y[1]))=abs((x[3]-x[4])/(y[3]-y[4])) then r:=r+1
                                                                                                                   else
                                                 else
                            else if y[3]-y[4]=0 then r:=r+1;
            if y[4]-y[1]<>0 then if y[3]-y[2]<>0 then if abs((x[4]-x[1])/(y[4]-y[1]))=abs((x[3]-x[2])/(y[3]-y[2])) then r:=r+1
                                                                                                                   else
                                                 else
                            else if y[3]-y[2]=0 then r:=r+1;
         end;
assign(g,'trapez.out');
rewrite(g);
writeln(g,r);
close(g);
end.