const int PB = 4; 
const int led1 = 9; 
const int led2 = 10; 
const int led3 = 11; 
const int led4 = 12; 
int i = 0; 
 
void setup() { 
  Serial.begin(9600); 
  pinMode (PB, INPUT); 
  pinMode (led1, OUTPUT); 
  pinMode (led2, OUTPUT); 
  pinMode (led3, OUTPUT); 
  pinMode (led4, OUTPUT); 
} 
void procedure() { 
  switch (i) { 
    case 1: 
      digitalWrite(led1, HIGH); 
      digitalWrite(led2, LOW); 
      digitalWrite(led3, LOW); 
      digitalWrite(led4, LOW); 
      break; 
    case 2: 
      digitalWrite(led1, HIGH); 
      digitalWrite(led2, HIGH); 
      digitalWrite(led3, LOW); 
      digitalWrite(led4, LOW); 
      break; 
    case 3: 
      digitalWrite(led1, HIGH); 
      digitalWrite(led2, HIGH); 
      digitalWrite(led3, HIGH); 
      digitalWrite(led4, LOW); 
      break; 
    case 4: 
      digitalWrite(led1, HIGH); 
      digitalWrite(led2, HIGH); 
      digitalWrite(led3, HIGH); 
      digitalWrite(led4, HIGH); 
      break; 
    default: 
      digitalWrite(led1, LOW); 
      digitalWrite(led2, LOW); 
      digitalWrite(led3, LOW); 
      digitalWrite(led4, LOW);       
      break; 
  } 
} 
 
void loop() { 
  int val = digitalRead(PB); 
  if (val == HIGH) { 
    i++; 
    delay(300); 
    while (val == HIGH) { 
      val = digitalRead(PB); 
      procedure(); 
    } 
    if (i == 5) { 
      i = 0; 
    } 
  } 
}