I am trying to learn how to create offsets with mouse movement and I am coming up with an error message ("Duplicate method setup() in type")  with the following script that I can't figure out:

void setup() {
  size(100, 100);
  smooth();
  noStroke();
}

void draw() {
  background(126);
  ellipse(mouseX, mouseY, 33, 33);
}

void setup() {
  size(100, 100);
  smooth();
  noStroke();
}

void draw() {
  background(126);
  ellipse(mouseX, 16, 33, 33);
  ellipse(mouseX+20, 50, 33, 33);
  ellipse(mouseX-20, 84, 33, 33);
}

Thanks, in advance, for your help!