int LV=1;

void setup() {
  // put your setup code here, to run once:
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);
pinMode(10, OUTPUT);
pinMode(7, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
if (digitalRead(7)==1) {
LV+=1;
delay(150);
}
if (LV==1) {
  digitalWrite(8, HIGH);
  digitalWrite(9, LOW);
  digitalWrite(10, LOW);
}
else if (LV==2) {
  digitalWrite(8, LOW);
  digitalWrite(9, HIGH);
  digitalWrite(10, LOW);
}
else if (LV==3){
  digitalWrite(8, LOW);
  digitalWrite(9, LOW);
  digitalWrite(10, HIGH);
}
else {
  LV=1;
}
}