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