const int L1 = 0;
const int L2 = 1;
const int L3 = 2;
const int L4 = 3;
const int L5 = 4;
const int L6 = 5;
const int L7 = 6;
const int L8 = 7;
const int L9 = 8;
const int L10 = 9;

const int L11 = 10;
const int L12 = 11;
const int L13 = 12;
const int L14 = 13;
const int L15 = A5;
const int L16 = A4;
const int L17 = A3;
const int L18 = A2;
const int L19 = A1;
const int L20 = A0;

void setup() {
  pinMode(L1, OUTPUT);
  pinMode(L2, OUTPUT);
  pinMode(L3, OUTPUT);
  pinMode(L4, OUTPUT);
  pinMode(L5, OUTPUT);
  pinMode(L6, OUTPUT);
  pinMode(L7, OUTPUT);
  pinMode(L8, OUTPUT);
  pinMode(L9, OUTPUT);
  pinMode(L10, OUTPUT);

  pinMode(L11, OUTPUT);
  pinMode(L12, OUTPUT);
  pinMode(L13, OUTPUT);
  pinMode(L14, OUTPUT);
  pinMode(L15, OUTPUT);
  pinMode(L16, OUTPUT);
  pinMode(L17, OUTPUT);
  pinMode(L18, OUTPUT);
  pinMode(L19, OUTPUT);
  pinMode(L20, OUTPUT);

}

void loop() {
  digitalWrite(L1, HIGH);
  delay(20);
  digitalWrite(L1, LOW);
  delay(20);
  digitalWrite(L2, HIGH);
  delay(20);
  digitalWrite(L2, LOW);
  delay(20);
  digitalWrite(L3, HIGH);
  delay(20);
  digitalWrite(L3, LOW);
  delay(20);
  digitalWrite(L4, HIGH);
  delay(20);
  digitalWrite(L4, LOW);
  delay(20);
  digitalWrite(L5, HIGH);
  delay(20);
  digitalWrite(L5, LOW);
  delay(20);
  digitalWrite(L6, HIGH);
  delay(20);
  digitalWrite(L6, LOW);
  delay(20);
  digitalWrite(L7, HIGH);
  delay(20);
  digitalWrite(L7, LOW);
  delay(20);
  digitalWrite(L8, HIGH);
  delay(20);
  digitalWrite(L8, LOW);
  delay(20); 
  digitalWrite(L9, HIGH);
  delay(20);
  digitalWrite(L9, LOW);
  delay(20);  
  digitalWrite(L10, HIGH);
  delay(20);
  digitalWrite(L10, LOW);
  delay(20);


  digitalWrite(L11, HIGH);
  delay(20);
  digitalWrite(L11, LOW);
  delay(20);
  digitalWrite(L12, HIGH);
  delay(20);
  digitalWrite(L12, LOW);
  delay(20);
  digitalWrite(L13, HIGH);
  delay(20);
  digitalWrite(L13, LOW);
  delay(20);
  digitalWrite(L14, HIGH);
  delay(20);
  digitalWrite(L14, LOW);
  delay(20);
  digitalWrite(L15, HIGH);
  delay(20);
  digitalWrite(L15, LOW);
  delay(20);
  digitalWrite(L16, HIGH);
  delay(20);
  digitalWrite(L16, LOW);
  delay(20);
  digitalWrite(L17, HIGH);
  delay(20);
  digitalWrite(L17, LOW);
  delay(20);
  digitalWrite(L18, HIGH);
  delay(20);
  digitalWrite(L18, LOW);
  delay(20); 
  digitalWrite(L19, HIGH);
  delay(20);
  digitalWrite(L19, LOW);
  delay(20);  
  digitalWrite(L20, HIGH);
  delay(20);
  digitalWrite(L20, LOW);
  delay(20);

}