#include <bits/stdc++.h> using namespace std; typedef long long ll; typedef pair<ll, ll> pll; const ll LOG = 31; const ll MOD = 1000000007; const ll inf = 1e17; const ll B = 2305843009213693951; #define db(x) cerr << #x << " = " << x << " | " #define dbg(x) cerr << #x << " = " << x << "\n" #define Algerian ios::sync_with_stdio(0); #define OI cin.tie(NULL); int main() { Algerian OI ll n, q; cin >> n >> q; vector<ll> a(q); for (ll& x : a) cin >> x; vector<bool> ahead(n); ll r = 0; for (ll i = 0; i < q; i++) { if (a[i] < 0) ahead[-a[i]] = 0; else { if (ahead[a[i]]) { r++; for (ll j = 0; j < n; j++) ahead[j] = 0; ahead[a[i]] = 1; } else ahead[a[i]] = 1; } } cout << r << "\n"; return 0; }