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

if k==1:
    print('0')

else:

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

else:

    ans=n-k
    print(ans) k==1 k 1 print('0') print '0' ans=n-k ans n-k n k print(ans) print ans k=map(int,input().split()) map(int,input().split()) k ans=n-k n-k ans n,k=map(int,input().split()) map(int,input().split()) n
n,k=map(int,input().split())

if k==1:
    print('0')

else:

    ans=n-k
    print(ans)