04. Clever Lily

package main

import "fmt"

func main() {
    var age int
    fmt.Scanln(&age)

    var machinePrice, toyPrice float64
    fmt.Scanln(&machinePrice)
    fmt.Scanln(&toyPrice)

    var sum = 0.0
    var toy = 0.0
    var birthday = 10.0

    for i := 3; i < age + 3; i++ {
        if i % 2 == 0 {
            sum += birthday - 1
            birthday += 10
        } else {
            toy++
        }
    }

    sum += toy * toyPrice

    if sum >= machinePrice {
        fmt.Printf("Yes! %.2f\n", sum - machinePrice)
    } else {
        fmt.Printf("No! %.2f\n", machinePrice - sum)
    }
}