N, K = map(int, input().split())
S = input()

def solve(N, K, S):
    if K <= N:
        return count_payment(N, K, S)[0]
    cost, atari = count_payment(N, N, S)
    m, r = divmod(K, N)
    cost2, atari2 = count_payment(N, r, S)
    return cost + max(cost - atari, 0) * (m-1) + max(cost2 - atari, 0)

def count_payment(N, K, S):
    '''K個のアイスを食べるために、購入するアイスの本数と、残りあたり本数をこたえる。
    '''
    cost = 0
    atari = 0
    for s in S[:K]:
        if atari:
            atari -= 1
        else:
            cost += 1
        if s == '1':
            atari += 1
        elif s == '2':
            atari += 2
    return cost, atari

print(solve(N, K, S))