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

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

if k == 1:
    print(0)
else:
    mx = n - k + 1
    ans = mx - 1
    print(ans)
