using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static string InputPattern = "Input5";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("5 4");
            WillReturn.Add("01200");
            //2
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("2 8");
            WillReturn.Add("10");
            //4
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("10 100");
            WillReturn.Add("2222222222");
            //1
        }
        else if (InputPattern == "Input4") {
            WillReturn.Add("2 5");
            WillReturn.Add("01");
            //3
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static int K;
    static char[] SArr;

    static void Main()
    {
        List<string> InputList = GetInputList();
        K = int.Parse(InputList[0].Split(' ').Last());
        SArr = InputList[1].ToCharArray();

        Console.WriteLine(Solve());
    }

    static int Solve()
    {
        int HonsuuSum = 0;
        int KounyuuCnt = 0;
        int AtariHonsuu = 0;

        //1箱分の処理を行う
        Action HitohakoSyori = () =>
        {
            foreach (char EachChar in SArr) {
                if (AtariHonsuu == 0) KounyuuCnt++;
                else AtariHonsuu--;

                if (EachChar == '1') AtariHonsuu++;
                if (EachChar == '2') AtariHonsuu += 2;

                if (++HonsuuSum == K) {
                    return;
                }
            }
        };

        //1箱目の処理を行う
        HitohakoSyori();

        //1箱目で指定本数に達した場合
        if (HonsuuSum == K) {
            return KounyuuCnt;
        }

        //持ち越した当たり本数を使っての
        //次の箱での購入数
        int SecondBoxKounyuuCnt = KounyuuCnt - AtariHonsuu;
        if (SecondBoxKounyuuCnt <= 0) return KounyuuCnt;

        //指定本数までの全箱数
        int TotalBoxCnt = K / SArr.Length;
        if (K % SArr.Length > 0) TotalBoxCnt++;

        //1箱目と最終箱以外の箱数
        int RestBoxCnt = TotalBoxCnt - 2;

        //1箱目と最終箱以外の箱を一気に処理
        if (RestBoxCnt > 0) {
            HonsuuSum += RestBoxCnt * SArr.Length;
            KounyuuCnt += RestBoxCnt * SecondBoxKounyuuCnt;
        }

        //最終箱の処理を行う
        HitohakoSyori();
        return KounyuuCnt;
    }
}