Problem adding Trigger

[jix]

HI

I have xml file that contains host items.triggers and graphs

in my trigger i have rows like the following

<trigger>
<description>POS1/0 Traffic White IN</description>
<type>0</type>
<expression>{Router_GSR:Port_InOctets_2.last(0)}<1500000 & {Router_GSR:Port_InOctets_2.last(0)}>0 </expression>
<url></url>
<status>0</status>
<priority>0</priority>
<comments></comments>
</trigger>

but when i try to import my template i got error

XML file contains errors. Fatal Error 68: StartTag: invalid element name [ Line: 2167 | Column: 59 ]

and on line 2167 :

<expression>{Router_GSR:Port_InOctets_2.last(0)}<1 500000 & {Router_GSR:Port_InOctets_2.last(0)}>0 </expression>

the problem come from & sign
how can i import my trigger with the following expression?