<?xml version="1.0" ?><!DOCTYPE nta PUBLIC '-//Uppaal Team//DTD Flat System 1.0//EN' 'http://www.docs.uu.se/docs/rtmv/uppaal/xml/flat-1_0.dtd'><nta><declaration>//Insert declarations of global clocks, variables, constants and channels.

urgent chan b;
clock x,y;
int[0,3] v=0,w=0;</declaration><template><name x="5" y="5">P</name><declaration>//Insert local declarations of clocks, variables and constants.
</declaration><location id="id0" x="0" y="-216"></location><location id="id1" x="0" y="-448"><name x="16" y="-464">p0</name></location><location id="id2" x="0" y="-320"><name x="16" y="-336">p1</name></location><init ref="id1"/><transition><source ref="id2"/><target ref="id0"/><label kind="synchronisation" x="-60" y="-283">b?</label></transition><transition><source ref="id1"/><target ref="id2"/><label kind="assignment" x="-60" y="-384">x:=0</label></transition></template><template><name>Q</name><location id="id3" x="0" y="0"><name x="16" y="-16">q3</name></location><location id="id4" x="-128" y="0"><name x="-112" y="-16">q2</name></location><location id="id5" x="-64" y="-128"><name x="-48" y="-144">q1</name></location><location id="id6" x="-64" y="-256"><name x="-48" y="-272">q0</name></location><init ref="id6"/><transition><source ref="id5"/><target ref="id3"/><label kind="assignment" x="-16" y="-80">v:=3</label></transition><transition><source ref="id5"/><target ref="id4"/><label kind="synchronisation" x="-144" y="-80">b!</label><label kind="assignment" x="-144" y="-64">v:=2</label></transition><transition><source ref="id6"/><target ref="id5"/><label kind="assignment" x="-48" y="-208">y:=0, v:=1</label><nail x="-64" y="-192"/></transition></template><template><name>R</name><location id="id7" x="0" y="64"><name x="16" y="48">r1</name></location><location id="id8" x="0" y="-64"><name x="16" y="-80">r0</name></location><init ref="id8"/><transition><source ref="id8"/><target ref="id7"/><label kind="assignment" x="16" y="-16">w:=v</label></transition></template><instantiation>//Insert process assignments.
</instantiation><system>//Edit system definition.
system P,Q,R;</system></nta>