N, K = map(int, input().split())

if N < K or K==1:
  print(0)
else:
  print(N-K) N, K = map(int, input().split()) N map(int, input().split()) map int input().split() ().split () input split K if N < K or K==1:
  print(0)
else:
  print(N-K) N < K or K==1 N < K N K K==1 K 1 print(0) print 0 print(N-K) print N-K N K K = map(int, input().split()) map(int, input().split()) K N, K = map(int, input().split()) map(int, input().split()) N
N, K = map(int, input().split())

if N < K or K==1:
  print(0)
else:
  print(N-K)