import java.util.Scanner;
public class CALC{
	public static void main(String args[]){
		double x;
		double y;
		String z;
		Scanner sc=new Scanner(System.in)
		System.out.println("输入第一个数：");
		x=sc.nextDouble();
		System.out.println("输入运算符：");
		z=sc.next();
		System.out.println("输入第二个数：");
		y=sc.nextDouble();
		System.out.print("结果是：");
		switch(z){
		case"+":System.out.println(x+y);
			break;
		case"-":System.out.println(x-y);
			break;
		case"*":System.out.println(x*y);
			break;
		case"/":System.out.println(x/y);
			break;
		}
	}
}