Program stergeri;
Var f,ff:text;
    n,m,k,kk,i,fff,kkk:longint;
    a,b,c:array[1..1000000] of longint;
Begin
 assign(f,'stergeri.in');
 reset(f);
 assign(ff,'stergeri.out');
 rewrite(ff);
 readln(f,n,m,k);
 kk:=k;
 for i:=1 to m do
    begin readln(f,a[i],b[i]); c[i]:=b[i]-a[i]+1; end;
 for i:=m downto 1 do if a[i]<=kk then kk:=kk+c[i];
 Writeln(ff,kk);


 {for i:=1 to m do
    if k>=a[i] then kk:=kk+c[i];
 fff:=0;
 while(fff=0) do
    begin
     fff:=1;
     kkk:=kk;
     for i:=1 to m do
        if kk>b[i] then kk:=kk-c[i]
                   else if (kk<=b[i])and(kk>=a[i]) then
                       if kkk+c[i]<=n then
                         begin
                          fff:=0;
                          kkk:=kkk+b[i]-a[i]+1;
                          break;
                         end;
     kk:=kkk-kk+k;
     if kk<>kkk then fff:=0;
    end;
 Writeln(ff,kkk);}
 close(ff);
 close(f);
End.