#include <bits/stdc++.h>
#include <fstream>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define endl '\n'
#define pb push_back
#define INF 200000000
#define fi first
#define se second
//#define cin fin
//#define cout fout
using namespace std;
//double const EPS = 1e-14;
typedef long long ll;
//const ll P = 10007;
//const ll mod = 1e9 + 7;
//using namespace __gnu_pbds;
//typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set; // find_by_order, order_of_key
int main()
{
ios_base::sync_with_stdio(0); cout.tie(0); cin.tie(0);
int n, q; cin >> n >> q;
set<int> st; int ans = 0;
while(q--) {
int x; cin >> x;
if(x > 0) {
if(st.find(x) != st.end()) {
ans++;
st.clear();
}
st.insert(x);
}
else {
x *= -1;
if(st.find(x) != st.end()) st.erase(x);
}
}
cout << ans << endl;
return 0;
}
