int rowvalue = 6;
  int keyvalue =0;

void setup() {
  // put your setup code here, to run once:
  pinMode (2,OUTPUT);
  pinMode (3,OUTPUT);
  pinMode (4,OUTPUT);
  pinMode (5,OUTPUT);
  pinMode (6,INPUT_PULLUP);
  pinMode (7,INPUT_PULLUP);
  pinMode (8,INPUT_PULLUP);
  pinMode (9,INPUT_PULLUP);
  pinMode (10,INPUT_PULLUP);
  digitalWrite(2,HIGH);
  digitalWrite(3,HIGH);
  digitalWrite(4,HIGH);
  digitalWrite(5,HIGH);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  for ( int column = 2; column <6; column++) 
  {
    digitalWrite(column,LOW);
    

     for ( int row =6; row <11; row ++)
     {
       if (digitalRead (row)==LOW) 
       {
       keyvalue = rowvalue + column;
     }
       rowvalue = rowvalue + 4;

     }
  rowvalue = 6; 
  digitalWrite (column, HIGH);
  }
  
  Serial.println(keyvalue);
  keyvalue = 0;
  rowvalue = 6; 
  delay (100);
}