diff --git a/role.guard.js b/role.guard.js
index 9ff9405..37fa6b3 100644
--- a/role.guard.js
+++ b/role.guard.js
@@ -2,8 +2,14 @@ var battle = require('battle')
 
 var roleGuard = {
     getLastFlag: function(){
-
-        return 4; // TODO. calculate me.
+        let patrolFlags = _.filter(Game.flags, function(flag){
+            return flag.name.indexOf("patrol_") == 0;
+        });
+        let flagNumbers = _.map(patrolFlags, function(flag){ 
+            return parseInt(flag.name.substring("patrol_".length, flag.name.length));
+        });
+        let max =  Math.max.apply(Math, flagNumbers);
+        return max;
     },
     run: function(creep){
         console.log(creep, 'running Guard')