int led=12;
 int PB=2;


void setup() {
  // put your setup code here, to run once:
pinMode(led, OUTPUT);
pinMode(PB, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
if(digitalRead(PB)==1)
{
  digitalWrite(led, HIGH);
}
else
digitalWrite(led, LOW);
}