#include <Keypad.h>

  char key[4][4] = {
    {'1','2','3','A'},
    {'4','5','6','B'},
    {'7','8','9','C'},
    {'*','0','#','D'}
  };

  byte row[4]={9,8,7,6};
  byte col[4]={5,4,3,2};

  Keypad mypad= Keypad(makeKeymap(key),row,col,4,4);

void setup() {
   Serial.begin(9600);

}

void loop() {
  char presskey = mypad.getKey();
  if(presskey){
    Serial.println(presskey);
  }
 

}