content: iesimoDigito :: Integer -> Integer -> Integer
  iesimoDigito n i = mod (div n (10^((cantDigitos n)-i))) 10
  
  cantDigitos :: Integer -> Integer
  cantDigitos n = auxCant n 0 
  
  auxCant :: Integer -> Integer -> Integer
  auxCant n c | mod n 10 == n = c+1
              | otherwise = auxCant (div n 10) (c+1)