n,k = map(int, input().split())
if k>=2:
    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>=2:
    print(n-k)
else:
    print(0) k>=2 k 2 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>=2:
    print(n-k)
else:
    print(0)