var n,m,k,i,j,x,y:longint; v:array[1..1000000000] of boolean; f:text;
begin
fillchar(v,sizeof(v),true);
assign(f,'stergeri.in'); reset(f);
read(f,n,m,k);
for i:=1 to m do begin
read(f,x,y);
j:=x-1;
repeat
      j:=j+1;
      if not(v[j]) then y:=y+1
                   else v[j]:=false;
until j=y;
end;
close(f);
i:=0;
repeat
i:=i+1;
if v[i] then k:=k-1;
until k=0;
assign(f,'stergeri.out'); rewrite(f);
write(f,i);
close(f)
end.