What was the difference between the number of shares at the beginning and end of year 2019?
{"": {"2019": "No. of Shares", "2018": "No. of Shares"}, "Number of shares at beginning of year": {"2019": 114758, "2018": 137227}, "Number of shares distributed to employees": {"2019": 45560, "2018": 42480}, "Number of shares transferred to main share registry and/or disposed of": {"2019": -44526, "2018": -64949}, "Number of shares at year end": {"2019": 115792, "2018": 114758}}
number_of_shares_at_year_end_2019 = df["Number of shares at year end"]["2019"]
number_of_shares_at_beginning_of_year_2019 = df["Number of shares at beginning of year"]["2019"]
answer = number_of_shares_at_year_end_2019 - number_of_shares_at_beginning_of_year_2019