program stergeri;
type
tabel=array [0..100001] of longint;
var
v,t:tabel;
n,m,i,k,x,y:longint;
f1,f2:text;
begin
assign (f1,'stergeri.in');
assign (f2,'stergeri.out');
reset (f1);
rewrite (f2);
readln (f1,n,m,k);
for i:=1 to m do
readln (f1,v[i],t[i]);
for i:=m downto 1 do begin
if v[i]<=k then k:=k+t[i]-v[i]+1;
end;
writeln (f2,k);
close (f1);
close (f2);
end.