var del:array[1..100000,1..2] of longint;
    n,d,k,i:longint;
begin
  assign(input,'stergeri.in'); reset(input);
  assign(output,'stergeri.out');rewrite(output);
  readln(n,d,k);
  for i:=1 to d do readln(del[i,1],del[i,2]);
  for i:=d downto 1 do
    if del[i,1]<=k then inc(k,del[i,2]-del[i,1]+1);
  writeln(k);
  close(input); close(output);
end.