function back(input) {
    let money = Number(input.shift());
    let n = Number(input.shift());
    let age = 17;
    for (let i = 1800; i <= n; i++) {

        if (i % 2 == 0) {
            age += 1;
            money -= 12000;
        } else {
            age += 1;
            money -= 12000 + (age * 50);
        }
    }
    if (money >= 0) {
        console.log(`Yes! He will live a carefree life and will have ${money.toFixed(2)} dollars left.`);
    } else {
        let neededMoney = Math.abs(money);
        console.log(`He will need ${(neededMoney.toFixed(2))} dollars to survive.`);
    }
}