void setup() {
  Serial.begin(115200);
  pinMode(16, OUTPUT);
  pinMode(17, OUTPUT);
  pinMode(18, OUTPUT);

  pinMode(34, INPUT);
  pinMode(35, INPUT);
  pinMode(32, INPUT);
}

void loop() {
  int VR1 = map(analogRead(34),0,4095,0,255);
  int VR2 = map(analogRead(35),0,4095,0,255);
  int VR3 = map(analogRead(32),0,4095,0,255);

  for(int i = 0 ; i <= VR1 ; i = i + 1){
    analogWrite(16,i);
  }
  for(int i = 0 ; i <= VR2 ; i = i + 1){
    analogWrite(17,i);
  }
  for(int i = 0 ; i <= VR3 ; i = i + 1){
    analogWrite(18,i);
  }
}