int Taster1  = 7;
int Taster2 = 8;
int L = 9;
int Merker;
int Gegen;
int Zeit;


void setup() {
  pinMode(Taster1, INPUT);
  pinMode(Taster2, INPUT);
  pinMode(L, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  if (digitalRead(Taster1) == HIGH) 
  {
    digitalWrite(L, HIGH);
    Merker = millis();
  }
  if (digitalRead(Taster2) == HIGH)
  {
    digitalWrite(L, LOW);
    Gegen = millis();
    Zeit = Gegen - Merker;
    Serial.println("Zeit: ");
    Serial.println(Zeit);
    delay(1000);
  }
}