#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; ll r = 0, reset = 0; vector<ll> last(n, -2); for (ll i = 0; i < q; i++) { if (a[i] < 0) { last[-a[i]] = -1; } else { if (last[a[i]] >= reset) { r++; reset = i; last[a[i]] = i; } else { last[a[i]] = i; } } } cout << r << "\n"; return 0; }