var a:array[1..1000] of longint;
    s,n,m,k,i,x,y,xx:longint;
    f:text;
    g:text;
begin
assign(f,'stergeri.in');reset(f);
assign(g,'stergeri.out');rewrite(g);
read(f,n,m,k);
read(f,x,y);
xx:=x;
s:=y-x+1;
for i:=1 to m-1 do begin
                 read(f,x,y);
                 If x<xx then begin xx:=x;
                                    s:=s+y-xx+1;
                 end;
                     s:=s+y-x;
                 end;
for i:=1 to xx do a[i]:=i;
for i:=s to n do a[i]:=i;
write(g,a[k]);
close(f);
close(g);
end.