int red=2;
int yellow=3;
int green=4;

int buttonred=5;
int buttonyellow=6;
int buttongreen=7;

int readingred;

void setup() {
  Serial.begin(9600);

  pinMode(red, OUTPUT);
  pinMode(yellow, OUTPUT);
  pinMode(green, OUTPUT);
  pinMode(buttonred, INPUT_PULLUP);
  pinMode(buttonyellow, INPUT_PULLUP);
  pinMode(buttongreen, INPUT_PULLUP);

}

void loop() {

readingred=digitalRead(buttonred);
Serial.println(readingred);

if(readingred==0){
  digitalWrite(red, HIGH);
}else{
  digitalWrite(red, LOW);
}

}