def stringToBin(string):
    number = 0
    mul = 1
    for i in range(len(string) - 1, -1, -1):
        if string[i] == '1':
            number += mul
        mul *= 2
    return number

def countOne(number):
    c = 0
    while number != 0:
        if number%2 == 1:
            c += 1
        number = number // 2 
    return c
    
        
if __name__ == "__main__":
    n, k = [int(x) for x in input("").split()]
    string = input("")
    number = stringToBin(string)
    options = 0

    for i in range(2**n):
        if countOne(number + i) == k:
            options += 1

    print(options)