package mathtraning;
import java.util.Scanner;
/**
 *
 * @author Roy
 */
public class Mathtraning {
    public static void main(String[] args) {
       Scanner in = new Scanner(System.in);
        System.out.println("Enter a function: mx + n");
        String function = in.next();
        char x = 'x';
        String d = "";
        for(int i=0;i<function.length();i++){
        if(function.charAt(i)==x){
           char num = function.charAt(i-1);
             d = d + num;
        }

    System.out.println(d);
        }
    }
}