program stergeri;
{$APPTYPE CONSOLE}
uses
  SysUtils;
var c,q,x,y,i,j,n,m,k:Longint;
    fin,fout:text;
    v:array [1..100000] of byte;
{*----------------------------------*}
begin
        assign(fin,'stergeri.in'); reset(fin);
        assign(fout,'stergeri.out'); rewrite(fout);

        readln(fin,n,m,k);
        For i:=1 to n do v[i]:=1;//generez

        For q:=1 to m do//elimin
        begin
                readln(fin,x,y);
                c:=0;
                i:=0;
                while c < y do
                begin
                        inc(i);
                        if v[i] = 1 then inc(c);
                        if (c >= x) and (c <= y) then v[i]:=0;
                end;
        end;

        c:=0;
        for i:=1 to n do
        begin
                if v[i] = 1 then inc(c);
                if c = k then write(fout,i);
        end;

        close(fin);
        close(fout);
end.