program Project2;

{$APPTYPE CONSOLE}

uses
  SysUtils;

type mas=array[1..200000,1..2]of longint;
var
a:mas;
n,i,j,res:longint;

procedure swap(var a,b:longint);
var key:longint;
begin
key:=a;
a:=b;
b:=key;
end;


function partition(var A:mas;p,r:longint):longint;
var x,i,j:longint;
begin
x:=A[r,1];
i:=p-1;
for j:=p to r-1 do
if (A[j,1]<x) or((A[j,1]=x)and(a[j,2]<A[r,2])) then begin i:=i+1; swap(A[i,1],A[j,1]);swap(A[i,2],A[j,2]); end;
swap(A[i+1,1],A[r,1]);swap(A[i+1,2],A[r,2]);
partition:=i+1;

end;


procedure qsort(var A:mas;p,r:longint);
var q:longint;
begin
if p<r then
begin
q:=partition(A,p,r);
qsort(A,p,q-1);
qsort(A,q+1,r);
end;
end;

begin
  assign(input,'task.in');
reset(input);
read(n);
for i:=1 to n do
begin
read(a[i,1],a[i,2]);
if a[i,1]>a[i,2] then swap(a[i,1],a[i,2]);
end;
close(input);

qsort(a,1,n);
for i:=2 to n do
if a[i,2]>=a[i-1,2]then inc(res);
assign(output,'task.out');
rewrite(output);
writeln(res);
close(output);




end.