Java Help

import java.util.Scanner;
public class Calculator {
	public static void main(String args[]) {
		Scanner input=new Scanner(System.in);
		System.out.println("Welcome to My Multi Calculator");
        System.out.println("Here are the choices:");
        System.out.println("(1) Convert Pounds to Kilograms");
        System.out.println("(2) Convert USD to Euro");
        System.out.println("(3) Convert Degrees F to C");
        System.out.println("(4) Calculate 20% gratuity on a bill");
        System.out.println("(5) Calculate if a number is prime");
        System.out.println("(6) Calulate the absolute difference of two numbers");
        System.out.println("(7) Quit");

        if (input.equals("1")) {
        	//System.out.println("1");
        	System.out.println("Input amount:");
            double size = input.nextInt();
            System.out.println("Answer: "+ size*0.453592);
            }
        if (input.equals("2")) {
        	System.out.println("2");
            }
        if (input.equals("3")) {
        	System.out.println("3");
            }
        if (input.equals("4")) {
        	System.out.println("4");
            }
        if (input.equals("5")) {
        	System.out.println("5");
            }
        if (input.equals("6")) {
        	System.out.println("6");
            }
        if (input.equals("7")) {
        	System.out.println("7");
	}
	}
}