my_input = '700\n10\n1'

my_input = my_input.split('\n')
n_person = int(my_input[0])
n_boat = int(my_input[1])
n_ferries = int(my_input[2])

total_save = n_ferries * 500 + n_boat * 4

my_output = n_person - total_save

print(my_output)