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

char abc[27] = {'a','b','c','d','e',
                'f','g','h','i','j',
                'k','l','m','n','o',
                'p','q','r','s','t',
                'u','v','w','x','y',
                'z'};                         

int front = 0; 
int buttonStateup = 0;
int buttonStatedown = 0;
int num = 0;

LiquidCrystal_I2C lcd(0x27,20,4);  

void setup()
{
  pinMode(7, INPUT);
  pinMode(6, INPUT);
  lcd.init();
  lcd.backlight(); 
  lcd.clear();
  
}

void loop()
{
  front = 12;
  int pos = front;
  while(buttonStateup == 0 or buttonStatedown == 0){
    buttonStateup = digitalRead(7);
    buttonStatedown = digitalRead(6);
    lcd.setCursor(0,1);
    for(int i = 0; i <= 15; i++){
      if (pos < 26){
        pos = front + i;
        num = front + i;
      }
      else if(pos >= 26){
        pos = front + i;
        num = front + i - 26;
      }
      lcd.print(abc[num]);
    }
  }
  while(buttonStateup == 0 or buttonStatedown == 0){

  }
}