var     n,i     :longint;
        ok1,ok2 :boolean;
        x,y     :array[0..15] of longint;

begin
        read(n);
        ok1:=true;
        ok2:=true;
        for i:=1 to n do
        begin
                read(x[i],y[i]);
                if x[i]<>x[1] then ok1:=false;
                if y[i]<>y[1] then ok2:=false;
        end;
        if (not ok1) and (not ok2) then write('NO') else write('YES');
end.