void setup() {
pinMode(4, OUTPUT);
pinMode(7, OUTPUT);
pinMode(8, OUTPUT);
pinMode(12, OUTPUT);
pinMode(2, INPUT);
}

void loop() {
if(digitalRead(2)==HIGH){
  digitalWrite(4, HIGH);
  delay(1000);
  digitalWrite(4, LOW);
}
else if(digitalRead(2)==HIGH){
  digitalWrite(7, HIGH);
  delay(1000);
  digitalWrite(7, LOW);
}
 else if(digitalRead(2)==HIGH){
  digitalWrite(8, HIGH);
  delay(1000);
  digitalWrite(8, LOW);
 }
  else if(digitalRead(2)==HIGH){
  digitalWrite(12, HIGH);
  delay(1000);
  digitalWrite(12, LOW);
 }
}