int btn1 = 5;
int btn2 = 4;
int btn3 = 3; 
int led = 2;

int password = 0; // 11233


void setup() {
Serial.begin(9600);
pinMode(led, OUTPUT);
pinMode(btn1, INPUT);
pinMode(btn2, INPUT);
pinMode(btn3, INPUT);
digitalWrite(btn1, HIGH);
digitalWrite(btn2, HIGH);
digitalWrite(btn3, HIGH);

}

void loop() {
int btn1state = digitalRead(btn1);
int btn2state = digitalRead(btn2);
int btn3state = digitalRead(btn3);

if (btn1state == 0){
password = 5;
}

if (btn2state == 0){
password = password*5;
}

if (btn3state == 0){
password = password*10;
}

if (password == 2500){
digitalWrite(led, HIGH);
}
Serial.println(password);
delay(200);
}