type stergeri=record
     x,y:longint;
     end;

var a:array[1..100000] of stergeri;
    f,g:text;
    n,k,i,poz:longint;

begin
 assign(f,'stergeri.in'); reset(f);
 assign(g,'stergeri.out'); rewrite(g);
 read(f,n,k,poz);
 for i:=1 to k do
  read(f,a[i].x,a[i].y);
 for i:=k downto 1 do
  if a[i].x<=poz then
   poz:=poz+a[i].y-a[i].x+1;
 writeln(g,poz);
 close(f); close(g);
end.