How much more was the balance at march 31, 2019 for Severance & payroll related charges than lease abandonment charges?
{"Balance at March 31, 2018": {"Lease abandonment charges": "$\u2014", "Severance & payroll related charges": "$\u2014", "Total": "$\u2014"}, "Restructuring charges": {"Lease abandonment charges": 1034, "Severance & payroll related charges": 14606, "Total": 15640}, "Payments": {"Lease abandonment charges": -540, "Severance & payroll related charges": -12642, "Total": -13182}, "Accrual reversals": {"Lease abandonment charges": "\u2014", "Severance & payroll related charges": -875, "Total": -875}, "Balance at March 31, 2019": {"Lease abandonment charges": 494, "Severance & payroll related charges": 1089, "Total": 1583}}
balance_march_31_2019_severance = df["Balance at March 31, 2019"]["Severance & payroll related charges"]
balance_march_31_2019_lease_abandonment = df["Balance at March 31, 2019"]["Lease abandonment charges"]
answer = balance_march_31_2019_severance - balance_march_31_2019_lease_abandonment