n, k = map(int, input().split())

if k!=1:
    print(n-k)
else:
    print('0') n, k = map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split k if k!=1:
    print(n-k)
else:
    print('0') k!=1 k 1 print(n-k) print n-k n k print('0') print '0' n, k = map(int, input().split()) map(int, input().split()) n k = map(int, input().split()) map(int, input().split()) k
n, k = map(int, input().split())

if k!=1:
    print(n-k)
else:
    print('0')