Error with include router in underscore backbone - backbone.js

Question

Trying to use underscore in project with backbone, but receive an error:
Uncaught TypeError: undefined is not a function
In my view, because variable Router undefined. I am new one in backbone and underscore, so please help me, maby something need to change in my code.
main.js
require.config({
paths: {
jquery: 'lib/jquery-2.1.1',
underscore: 'lib/underscore',
backbone: 'lib/backbone',
view: 'view/view'
},
shim: {
'backbone': {
deps: ['jquery','underscore'],
exports: 'Backbone'
}
}
});
require([
'app'
], function(App){
App.initialize();
});
app.js
define([
'router' // Request router.js
], function(Router) {
var initialize = function() {
Router.initialize();
};
return {
initialize: initialize
};
});
router.js
define([
'backbone',
'model/model',
'view'
], function(Backbone, appState) {
var router = Backbone.Router.extend({
routes: {
"": "selected_currency",
"!/": "selected_currency",
"!/finish": "finish"
},
selected_currency: function() {
appState.set({state: "selected_currency"});
},
finish: function () {
appState.set({state: "finish"});
}
});
Backbone.history.start();
return router;
});
/model/model.js
define([
'underscore',
'backbone'
], function(_, Backbone) {
var AppState = Backbone.Model.extend({
defaults: {
currencies: ['USD', 'EUR'],
selected_currency: '',
state: "selected_currency"
},
url: '/site/create-account'
});
return new AppState();
});
view/view.js
define([
'jquery',
'underscore',
'backbone',
'router', // Request router.js
'model/model'
], function($, _, Backbone, Router, appState) {
var Block = Backbone.View.extend({
el: $("#block"),
templates: {
"selected_currency": _.template($('#step_1').html()),
"finish": _.template($('#step_1_complete').html() + $('#step_2').html())
},
events: {
"click button": "get_currency"
},
initialize: function() {
this.model.bind('change', this.render, this);
},
get_currency: function() {
var currency = this.$el.find("[name=currency]").val();
appState.set({selected_currency: currency});
appState.fetch({
data: {'currency': appState.get('selected_currency')},
type: 'POST'
});
appState.once('sync error', function(model) {
this.model.set({"state": "finish"});
}, this);
},
render: function() {
var state = this.model.get("state");
$(this.el).html(this.templates[state](this.model.toJSON()));
return this;
}
});
new Block({model: appState});
var router = new Router();
appState.trigger("change");
appState.bind("change:state", function() {
var state = this.get("state");
if (state == "selected_currency")
router.navigate("!/", false);
else
router.navigate("!/" + state, false);
});
});