<?php
// your code goes here
$json = '{"response":[{"id":398262775,"first_name":"Некий","last_name":"Тип","photo_50":"https:\/\/pp.userapi.com\/c637131\/v637131775\/1ebb0\/0b3sHJcHiD0.jpg","photo_max_orig":"https:\/\/pp.userapi.com\/c637131\/v637131775\/1ebae\/jsx-Xgx7h5o.jpg"}]}';
var_dump($data['response'][0]['first_name']);
PD9waHAKCi8vIHlvdXIgY29kZSBnb2VzIGhlcmUKJGpzb24gPSAneyJyZXNwb25zZSI6W3siaWQiOjM5ODI2Mjc3NSwiZmlyc3RfbmFtZSI6ItCd0LXQutC40LkiLCJsYXN0X25hbWUiOiLQotC40L8iLCJwaG90b181MCI6Imh0dHBzOlwvXC9wcC51c2VyYXBpLmNvbVwvYzYzNzEzMVwvdjYzNzEzMTc3NVwvMWViYjBcLzBiM3NISmNIaUQwLmpwZyIsInBob3RvX21heF9vcmlnIjoiaHR0cHM6XC9cL3BwLnVzZXJhcGkuY29tXC9jNjM3MTMxXC92NjM3MTMxNzc1XC8xZWJhZVwvanN4LVhneDdoNW8uanBnIn1dfSc7CiRkYXRhID0ganNvbl9kZWNvZGUoJGpzb24sIHRydWUpOwp2YXJfZHVtcCgkZGF0YVsncmVzcG9uc2UnXVswXVsnZmlyc3RfbmFtZSddKTs=