#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
int x;
long m,t;
int start;
LiquidCrystal_I2C lcd(0x27,16,2);  
void setup(){
  pinMode(2, INPUT_PULLUP);
  pinMode(3, INPUT_PULLUP);
  lcd.init();                     
  lcd.backlight();
  lcd.print(0);
}
void loop(){
  if (digitalRead(2) == 0) {
    while (digitalRead(2) == 0) {
        delay(10);
      }  
    if (start == 0){
      start = 1;
      t = millis();
      lcd.clear();
      lcd.print("...");
    }
    else {
      start = 0;
      lcd.clear();
      m = m + (millis()-t)/1000;
      lcd.print(m);
    }
  }
  if (digitalRead(3) == 0){
    lcd.clear();
    lcd.print(0);
    start = 0;
    m = 0;
    delay(100);
  }
}