View Code of Problem 104

import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner in = new Scanner(System.in);
		while(in.hasNext()) {
			float n=in.nextInt()*1000;
			float v1=in.nextInt();
			float v2=in.nextInt();
			float t=in.nextInt();
			if(v1-v2<=0) {
				System.out.println("NO");
			}else {
				float time = n/(v1-v2);
				if(time<=t) {
					System.out.println(String.format("%.2f", time));
				}else {
					System.out.println("NO");
				}
			}
		}
	}
}