package main

import (
        "bufio"
        "fmt"
        "os"
        "strconv"
)

func nextInt() int {
        i, e := strconv.Atoi(nextString())
        if e != nil {
                panic(e)
        }
        return i
}

func nextString() string {
        var sc = bufio.NewScanner(os.Stdin)
        sc.Split(bufio.ScanWords)
        sc.Scan()
        return sc.Text()
}
func main() {
        var H, W, N, K int

        fmt.Scan(&H)
        fmt.Scan(&W)
        fmt.Scan(&N)
        fmt.Scan(&K)

        if H*W%N == K%N {
                fmt.Println("YES")
        } else {
                fmt.Println("NO")
        }
}