# coding: utf-8
n, k = map(int,input().split())
n -= k
if k==1:
    print(0)
else:
    print(n) n, k = map(int,input().split()) n map(int,input().split()) map int input().split() ().split () input split k n -= k n k if k==1:
    print(0)
else:
    print(n) k==1 k 1 print(0) print 0 print(n) print n n, k = map(int,input().split()) map(int,input().split()) n k = map(int,input().split()) map(int,input().split()) k n -= k k n
# coding: utf-8
n, k = map(int,input().split())
n -= k
if k==1:
    print(0)
else:
    print(n)
