# include "Keypad.h"
const byte ROWS=4;
const byte COLS=4;
char Keys [ROWS][COLS]={
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rPins[ROWS]={9,8,7,6};
byte cPins[COLS]={5,4,3,2};
Keypad keypad=Keypad(makeKeymap(keys),rPins,cPins,ROWS,COLS);
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
char key=keypad.getKey();
if (key!=NO_KEY)
Serial.println(key);
}