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)
