//~~~~~~~~~~~~~MJ®™~~~~~~~~~~~~~
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#define rep1(n) for(ll i=0; i<(ll)(n); ++i)
#define rep2(i,n) for(ll i=0; i<(ll)(n); ++i)
#define rep3(i,a,b) for(ll i=(ll)(a); i<(ll)(b); ++i)
#define rep4(i,a,b,c) for(ll i=(ll)(a); i<(ll)(b); i+=(c))
#define cut4(a,b,c,d,e,...) e
#define rep(...) cut4(__VA_ARGS__,rep4,rep3,rep2,rep1)(__VA_ARGS__)
#define per1(n) for(ll i=((ll)n)-1; i>=0; --i)
#define per2(i,n) for(ll i=((ll)n)-1; i>=0; --i)
#define per3(i,a,b) for(ll i=((ll)a)-1; i>=(ll)(b); --i)
#define per4(i,a,b,c) for(ll i=((ll)a)-1; i>=(ll)(b); i-=(c))
#define per(...) cut4(__VA_ARGS__,per4,per3,per2,per1)(__VA_ARGS__)
#define ll long long
#define ln cout<<endl
#define int long long
#define Code ios_base::sync_with_stdio(0);
#define by cin.tie(NULL);
#define Hayan cout.tie(NULL);
#define append push_back
#define all(x) (x).begin(),(x).end()
#define allr(x) (x).rbegin(),(x).rend()
#define vi vector<int>
#define ret(x) {cout<<x;return;}
#define ui map<int,int>
#define pi pair<int,int>
#define ff first
#define ss second
using namespace std;
template <typename T> using v = vector<T>;
const int INF = 1e18, MOD = 1e9+7, N = 2e5+7;
bool back[N];
int p[N];
void solve()
{
int n, k, e, m;
int ans=0;
cin >> n >> m;
vi a(m);
rep(m)
{
cin >> e;a[i]=e;
}
set<int> front;
// rep(n)front.insert(i+1);
int answer=0;
for (int i=0;i<m;i++)
{
if (a[i]>0)
{
if (front.count(a[i]))
{
ans++;
answer= max({ans-1,1ll,answer});
front.clear();
}
front.insert(a[i]);
}
else
{
front.extract(-a[i]);
}
}
cout << ans;
// cout << a.size();
// for (auto i: a){cout << i << " ";}
}
signed main(){
Code by Hayan
int ans=1;
//cout<<setprecision(1000);
// cin>>ans;
rep(ans){
// cout << "Case #" << i+1 << ": ";
solve();ln;}}
