var f,g:text;
   n,m,k,c,i:longint;
   x,y:array[0..100010]of longint;
begin
assign(f,'stergeri.in');
assign(g,'stergeri.out');
reset(f);
rewrite(G);
read(f,n,m,k);
n:=k;
for i:=1 to m do
  begin
    read(f,x[i],y[i]);
    inc(k,y[i]-x[i]+1);
  end;
for i:=1 to m do
  if (y[i]>k)then dec(k,y[i]-x[i]+1);
write(g,k);
close(f);
close(g);
end.