<?php

error_reporting(-1);

$creditBalance = 40000;
$percent = 1.03;
$servicePayment = 1000;
$monthlyPayment = 5000;
$paymentTotal = 0;

for ($month = 1; $month <= 20; $month ++) {
	$creditBalance = $creditBalance * $percent + $servicePayment;
	
	if ($creditBalance > $monthlyPayment) {
		$creditBalance = $creditBalance - $monthlyPayment;
		$paymentTotal = $paymentTotal + $monthlyPayment;
		echo "{$month} месяц долг составляет {$creditBalance}, всего выплачено {$paymentTotal} руб.\n";
	} else {
		$lastPay = $creditBalance;
		$creditBalance = $creditBalance - $lastPay;
		$paymentTotal = $paymentTotal + $lastPay;
		echo "{$month} месяц долг составляет {$creditBalance}, всего выплачено {$paymentTotal} руб.\nВыплачено успешно!\n";
		break;
	}
}