#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2); // set the LCD address to 0x27 for a 16 chars and 2 line display

#define button 2

int timerMode = 0;
long startTime;

void setup() {
  lcd.init();
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Press To Start");
  pinMode(button, INPUT);

}

void loop() {
  lcd.setCursor(0, 1);
  if (digitalRead(button) == HIGH) {
    startTime = millis();
    timerMode++;
    delay(400);
  }
  if (timerMode == 1) {
    lcd.setCursor(0, 1);
    lcd.print((millis() - startTime) / 1000.0);
  }
  if (timerMode > 1) {
    delay(2000);
    timerMode = 0;
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Press To Start");
  }
}