diff --git a/index.js b/index.js
index 0253060..c38efb8 100644
--- a/index.js
+++ b/index.js
@@ -5,26 +5,26 @@ var lib = require('./lib');
 var friends = [
     {
         name: 'Sam',
-        friends: ['Mat', 'Sharon'],
+        friends: ['Sharon', 'Mat'],
         gender: 'male',
         best: true
     },
     {
         name: 'Sally',
-        friends: ['Brad', 'Emily'],
+        friends: ['Emily', 'Brad'],
         gender: 'female',
         best: true
     },
-    {
-        name: 'Mat',
-        friends: ['Sam', 'Sharon'],
-        gender: 'male'
-    },
     {
         name: 'Sharon',
         friends: ['Sam', 'Itan', 'Mat'],
         gender: 'female'
     },
+    {
+        name: 'Mat',
+        friends: ['Sam', 'Sharon'],
+        gender: 'male'
+    },
     {
         name: 'Brad',
         friends: ['Sally', 'Emily', 'Julia'],
diff --git a/lib.js b/lib.js
index 60f30ab..9787333 100644
--- a/lib.js
+++ b/lib.js
@@ -1,15 +1,74 @@
 'use strict';
 
-/**
+function getFriendByName(name, friends) {
+    return friends.filter(function (friend) {
+        return friend.name === name;
+    })[0];
+}
+
+function getInvitedFriends(friends) {
+    var currentFriendsCircle = friends.filter(function (friend) {
+        return friend.best;
+    });
+    var result = [];
+    var currentLevel = 1;
+    var friendsNames = [];
+    while (currentFriendsCircle.length !== 0) {
+        var nextLevelNames = [];
+        currentFriendsCircle = currentFriendsCircle.sort(function (a, b) {
+            return a.name.localeCompare(b.name);
+        });
+        for (var i = 0; i < currentFriendsCircle.length; i++) {
+            var friend = currentFriendsCircle[i];
+            result.push({
+                level: currentLevel,
+                friend: friend
+            });
+            friendsNames.push(friend.name);
+            nextLevelNames = nextLevelNames.concat(friend.friends);
+        }
+        currentFriendsCircle = nextLevelNames.filter(function (name) {
+            return friendsNames.indexOf(name) === -1;
+        })
+        .map(function (name) {
+            return getFriendByName(name, friends);
+        });
+        currentLevel++;
+    }
+
+    return result;
+}
+
+ /**
  * Итератор по друзьям
  * @constructor
  * @param {Object[]} friends
  * @param {Filter} filter
  */
 function Iterator(friends, filter) {
-    console.info(friends, filter);
+    if (!(filter instanceof Filter)) {
+        throw new TypeError('no filter');
+    }
+    this.invitedFriends = getInvitedFriends(friends)
+    .filter(function (item) {
+        return filter.test(item.friend);
+    });
+
+    this.index = 0;
 }
 
+Iterator.prototype.done = function () {
+    return this.invitedFriends.length <= this.index;
+};
+
+Iterator.prototype.next = function () {
+    if (this.done()) {
+        return null;
+    }
+
+    return this.invitedFriends[this.index++].friend;
+};
+
 /**
  * Итератор по друзям с ограничением по кругу
  * @extends Iterator
@@ -19,15 +78,23 @@ function Iterator(friends, filter) {
  * @param {Number} maxLevel – максимальный круг друзей
  */
 function LimitedIterator(friends, filter, maxLevel) {
-    console.info(friends, filter, maxLevel);
+    Iterator.call(this, friends, filter);
+
+    this.invitedFriends = this.invitedFriends.filter(function (item) {
+        return item.level <= maxLevel;
+    });
 }
 
+LimitedIterator.prototype = Object.create(Iterator.prototype);
+
 /**
  * Фильтр друзей
  * @constructor
  */
 function Filter() {
-    console.info('Filter');
+    this.test = function () {
+        return true;
+    };
 }
 
 /**
@@ -36,8 +103,11 @@ function Filter() {
  * @constructor
  */
 function MaleFilter() {
-    console.info('MaleFilter');
+    this.test = function (item) {
+        return item.gender === 'male';
+    };
 }
+MaleFilter.prototype = Object.create(Filter.prototype);
 
 /**
  * Фильтр друзей-девушек
@@ -45,8 +115,11 @@ function MaleFilter() {
  * @constructor
  */
 function FemaleFilter() {
-    console.info('FemaleFilter');
+    this.test = function (item) {
+        return item.gender === 'female';
+    };
 }
+FemaleFilter.prototype = Object.create(Filter.prototype);
 
 exports.Iterator = Iterator;
 exports.LimitedIterator = LimitedIterator;
diff --git a/lib.spec.js b/lib.spec.js
index 91de106..92814e9 100644
--- a/lib.spec.js
+++ b/lib.spec.js
@@ -67,7 +67,8 @@ describe('Итераторы', function () {
         while (!femaleIterator.done()) {
             invitedFriends.push(femaleIterator.next());
         }
-
+        // console.info(friends);
+        // console.info(invitedFriends);
         assert.deepStrictEqual(invitedFriends, [
             [friend('Sam'), friend('Sally')],
             [friend('Brad'), friend('Emily')],