#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 100;
int n, val[4 * N];
void upd(int l, int r, int x, int v = 1, int s = 1, int e = n){
if (r <= s || e <= l) return ;
if (l <= s && e <= r){
val[v] = x;
return ;
}
int mid = (s + e) / 2, lc = 2 * v, rc = lc + 1;
if (val[v] != -1)
val[lc] = val[rc] = val[v], val[v] = -1;
upd(l, r, x, lc, s, mid);
upd(l, r, x, rc, mid, e);
}
int get(int p, int v = 1, int s = 1, int e = n){
if (val[v] != -1) return val[v];
int mid = (s + e) / 2, lc = 2 * v, rc = lc + 1;
if (p < mid) return get(p, lc, s, mid);
return get(p, rc, mid, e);
}
int main(){
memset(val, -1, sizeof val);
ios::sync_with_stdio(0); cin.tie(0);
cin >> n;
for (int i = 1; i < n; i ++)
upd(i, i + 1, 1);
int q;
cin >> q;
int ans = 0;
while (q--){
int i;
cin >> i;
if (i < 0){
i = -i;
upd(i, i + 1, 1);
}
else{
if (get(i)){
upd(i, i + 1, 0);
}
else{
upd(1, n, 1);
upd(i, i + 1, 0);
ans++;
}
}
}
cout << ans << endl;
}
