program stergeri;
var f,g:Text;
    n,m,k,min,i,j,c,x,y,t:longint;
begin
assign(f,'stergeri.in');
assign(g,'stergeri.out');
reset(f);
rewrite(g);
read(f,n,m,k);
min:=maxlongint;
for j:=1 to m do
  begin
    read(f,x,y);
    t:=t+y-x+1;
    if(x<min)then min:=x;
  end;
c:=0;
i:=0;
while (c<k)do
  begin
    if (i=min-1)then i:=i+t;
    i:=i+1;
    c:=c+1;
  end;
write(g,i);
close(f);
close(g);
end.