text: import React from 'react';
  import { createAppContainer } from 'react-navigation';
  import { createStackNavigator } from 'react-navigation-stack';
  import MainScreen from './src/screens/MainScreen';
  
  const navigator=createStackNavigator(
    {
      Main:MainScreen,
    },
    {
      intialRouteName: 'Main',
      defaultNavigationOptions:{
        title: 'Tic Tac Toe'
      }
    },
  );
  
  export default createAppContainer(navigator);