// int led
int ledred=13;
int ledyellow=12;
int ledgreen=11;
// int pushbutton
int pbred=7;
int pbyellow=6;
int pbgreen=5;

void setup() {
  // pinmode led
  pinMode(ledred, OUTPUT);
  pinMode(ledyellow, OUTPUT);
  pinMode(ledgreen, OUTPUT);
  
  // pinmode pushbutton
  pinMode(pbred, INPUT_PULLUP);
  pinMode(pbyellow, INPUT_PULLUP);
  pinMode(pbgreen, INPUT_PULLUP);
}

void loop() {
  if(digitalRead(pbred)== LOW){
    digitalWrite(ledred, HIGH);
    digitalWrite(ledyellow, LOW);
    digitalWrite(ledgreen, LOW);
  }
  if(digitalRead(pbyellow)== LOW){
    digitalWrite(ledyellow, HIGH);
    digitalWrite(ledred, LOW);
    digitalWrite(ledgreen, LOW);
  }
  if(digitalRead(pbgreen)== LOW){
    digitalWrite(ledgreen, HIGH);
    digitalWrite(ledyellow, LOW);
    digitalWrite(ledred, LOW);
  }
}