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