#include<bits/stdc++.h>
using namespace std;
int n,m;
int a[1010];
int vis[1010];
int jiyi[1010];
int ans;
int dfs(int t,int step,int cnt,int tree)
{
	if(step <= m)
	{
		ans = max(ans,cnt);
	}
	if(step > m)
	{
		return 0;
	}	
	if(cnt <= jiyi[t])
	{
		return 0;
	}
	jiyi[t] = cnt;
	if(t >= n-1)
	{
		return 0;
	}

	if(a[t + 1] == tree)
	{
		dfs(t+1,step,cnt + 1,tree);	
		dfs(t+1,step+1,cnt,a[t+1]);
	}
	else
	{
		dfs(t+1,step,cnt,tree);
		dfs(t+1,step+1,cnt+1,a[t+1]);
	}
	return 0;
}
int main()
{
	cin >> n >> m;
	memset(jiyi,-1,sizeof jiyi);
	for(int i = 0;i<n;i++)
	{
		cin >> a[i];
	}
	if(a[0] == 1)
	{
		dfs(0,0,1,1);	
		dfs(0,1,0,2);
	}
	else
	{
		dfs(0,0,0,1);
		dfs(0,1,1,2);
	}
	cout << ans << '\n';
	return 0;
}

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