#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
int a[10000]={0},b[10000];
using namespace std;
int main()
{
	int n,m,i,j,dc,k=1,p,q;
	int flag=0,ans=0,t=1;
	cin>>n>>m;
	q=m;
	while (m--)
	{
		cin>>dc;
		b[k]=dc;
		k++;
	}
	m=q;
	while (t!=m+1)
	{
		for (i=1;i<=n;i++)
		{
			if (abs(a[i])==abs(b[t]))
			{
				flag=1;
			}
		}
		if (flag==0)
		{
			ans++;
			if (a[n]!=0)
			{
				for (i=1;i<=n;i++)
				{
					a[i]=a[i+1];
				}
				a[n]=b[t];
			}
			else
			{
				for (i=1;i<=n;i++)
				{
					if (a[i]==0)
					{
						p=i;
						break;
					}
				}
				a[p]=b[t];
			}
		}
		flag=0;
		t++;
	}
	cout<<ans<<endl;
	return 0;
}

有没有大佬帮个忙