var
	fi, fo : text;
  n, m, k, i, r : longint;
  s, d : array[1..100000] of longint;
begin
	assign(fi,'stergeri.in'); reset(fi);
  assign(fo,'stergeri.out'); rewrite(fo);
  readln(fi, n, m, k);
  for i := 1 to m do
  	readln(fi, s[i], d[i]);
  r := k; { raspunsul }
  for i := m downto 1 do
  	if s[i] <= r then
			inc(r,d[i]-s[i]+1);  	
  writeln(fo, r);
  close(fi); close(fo);
end.