#include <bits/stdc++.h>
using namespace std;
int n,k;
string s;
int passto;
int simurate(int pass,int end){
	int ans=0;
	for(int i=0;i<end;i++){
		if(pass)	pass--;
		else ans++;
		if(s[i]=='1') pass++;
		else if(s[i]=='2')	pass+=2;
	}
	passto=pass;
	return ans;
}
int main(){
	cin>>n>>k;
	cin>>s;
	int how=k%n;
	if(how==0)	how=n;
	int start=simurate(0,how);
	if(k>n){
		int cnt=0;
		for(int i=0;i<n;i++){
			if(s[i]=='1')	cnt++;
			else if(s[i]=='2')	cnt+=2;
		}
		int need=0;
		if(cnt<n)	need=n-cnt;
		start+=need*((k-1)/n);
	}
	cout<<start<<endl;
	return 0;
}