What is the difference in the Weighted Average Exercise Price between Exercised and Forfeited stock options?
{"Outstanding, December 31, 2018": {"Number of Shares": 4864836, "Weighted Average Exercise Price ($)": 17.76, "Weighted Average Remaining Contractual Term (Years)": "", "Aggregate Intrinsic Value of In-the- Money Options ($)": ""}, "Exercised": {"Number of Shares": -854524, "Weighted Average Exercise Price ($)": 15.78, "Weighted Average Remaining Contractual Term (Years)": "", "Aggregate Intrinsic Value of In-the- Money Options ($)": ""}, "Forfeited": {"Number of Shares": -3496, "Weighted Average Exercise Price ($)": 17.89, "Weighted Average Remaining Contractual Term (Years)": "", "Aggregate Intrinsic Value of In-the- Money Options ($)": ""}, "Outstanding, December 31, 2019": {"Number of Shares": 4006816.0, "Weighted Average Exercise Price ($)": 18.18, "Weighted Average Remaining Contractual Term (Years)": 3.71, "Aggregate Intrinsic Value of In-the- Money Options ($)": 78949941.0}, "Exercisable, December 31, 2019": {"Number of Shares": 3462664.0, "Weighted Average Exercise Price ($)": 17.86, "Weighted Average Remaining Contractual Term (Years)": 3.7, "Aggregate Intrinsic Value of In-the- Money Options ($)": 69349255.0}}
forfeited_weighted_avg_exercise_price = df["Forfeited"]["Weighted Average Exercise Price ($)"]
exercised_weighted_avg_exercise_price = df["Exercised"]["Weighted Average Exercise Price ($)"]
answer = forfeited_weighted_avg_exercise_price - exercised_weighted_avg_exercise_price