{
TASK: green
LANG: PASCAL
}
{$A+,B-,D+,E+,F-,G-,I+,L+,N+,O-,P-,Q-,R-,S+,T-,V+,X+,Y+}
{$M 16384,0,655360}

var
  a1x,a1y,a2x,a2y,a3x,a3y:longint;
  d1,d2,d3:extended;
  s,mins:extended;
  m,i,mini:longint;
  j:longint;
  f:text;
function len(a1x,a1y,a2x,a2y:longint):extended;
begin
  len:=sqrt(sqr(a1x-a2x)+sqr(a1y-a2y));
end;

function calcs(d1,d2,d3:extended):extended;
var
   p:extended;
begin
   p:=(d1+d2+d3)/2;
   p:=p*(p-d1)*(p-d2)*(p-d3);
   if p<0 then halt(0);
   calcs:=sqrt(p);
end;

begin
   mins:=1000000;
   assign(f,'');
   reset(F);
   read(F,m);
   while (m>0) do
   begin
      inc(i);
      read(f,a1x,a1y,a2x,a2y,a3x,a3y);
//      d1:=len(a1x,a2x,a1y,a2y);
//      d2:=len(a2x,a3x,a2y,a3y);
//      d3:=len(a1x,a3x,a1y,a3y);
//      s:=calcs(d1,d2,d3);
      for j:=4 to m do
      begin
          a2x:=a3x;a2y:=a3y;
          d1:=d2;
          read(f,a3x,a3y);
 //         d2:=len(a2x,a3x,a2y,a3y);
//          d3:=len(a1x,a3x,a1y,a3y);
//          s:=s+calcs(d1,d2,d3);
      end;
      if s<mins then
      begin
          mins:=s;
          mini:=i;
      end;
      read(f,m);
   end;
   close(F);
   writeln(mini);
end.
