How can i increment a value when the sensor it's on once.

hey i'm trying to do a code that counts 1 if the sensor is HIGH, but i've been trying and its going like 1,2,3,100, 200...

I want to ++1 just once in a value. Here is my try..

int valor=0;
void setup() {

Serial.begin(9600);

pinMode(3, INPUT_PULLUP);

}

void loop() {

int sensorVal = digitalRead(3);

if (sensorVal==1){
valor ++;
Serial.println(valor);

}
}

hey i'm trying to do a code that counts 1 if the sensor is HIGH

Is HIGH? Or BECOMES HIGH? Big difference.