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