<?php

error_reporting(-1);
mb_internal_encoding('utf-8');

function costOfHomoCredit($money, $payout){
	$sum = 0;
	for($i = 0; ($money*1.04+500)>$payout; $i++){
		$money = $money*1.04-$payout + 500;
		$sum += $payout;
	}
	if($money!=0) $sum+=$money;
	return $sum;
}

function costOfSoftBank($money, $payout){
	$sum = 0;
	for($i = 0; ($money*1.03+1000)>$payout; $i++){
		$money = $money*1.03-$payout + 1000;
		$sum += $payout;
	}
	if($money!=0) $sum+=$money;
	return $sum;
}

function costOfStrawberryBank($money, $payout){
	$sum = 0;
	$money += 7777;
	for($i = 0; ($money*1.02)>$payout; $i++){
		$money = $money*1.02-$payout;
		$sum += $payout;
	}
	if($money!=0) $sum+=$money;
	return $sum;
}

$creditSum = 39999;
$payout = 5000;
$homoCreditTotal = costOfHomoCredit($creditSum, $payout);
$softBankTotal = costOfSoftBank($creditSum, $payout);
$strawberryBankTotal = costOfStrawberryBank($creditSum, $payout);

echo "homoCredit: $homoCreditTotal\n";
echo "softBank: $softBankTotal\n";
echo "strawBerry: $strawberryBankTotal\n";