#include <iostream>
using namespace std;

main()
{
	int hours;
	int overtimeHours;
	int hourlyPay;

	cin >> hours;
	cin >> hourlyPay;

	int overtimeRate = 1.5 * hourlyPay;
	int overTimePay = overtimeHours * overtimeRate;
	int totalEarned = hours * hourlyPay;

	cin >> hours;
	cin >> hourlyPay;
	if (hours > 40)
	{
		overtimeHours = hours - 40;
		overTimePay = overtimeHours * overtimeRate;
		cout<<"\n Total amount earned is: "<< totalEarned + overtimePay;
	}

	else
	{
		cout<<"\nTotal amount earned is: ">> totalEarned endl;
	}