int throttle;
int ESC;

void setup() {

Serial.begin(9600);
Serial.println("BEGIN");
Serial.println();

pinMode(25, INPUT);

analogReadResolution (10);

}

void loop() {

if (analogRead(25) > throttle) {
  throttle += 3;

}

if (analogRead(25) < throttle) {
  throttle -= 4;

}

ESC = map(throttle, 0, 1023, 0, 255);

Serial.println(ESC);

}