#include<bits/stdc++.h>
using namespace std;
void place_l(vector < int > &ord, int x){
vector < int > cur;
for(int i : ord){
if(i == x)continue;
if(i == 0)cur.push_back(x);
cur.push_back(i);
}
ord = cur;
}
void place_r(vector < int > &ord, int x){
vector < int > cur;
for(int i : ord){
if(i == x)continue;
cur.push_back(i);
if(i == 0)cur.push_back(x);
}
ord = cur;
}
int get(vector < int > ord, int x){
for(int i = 0; i < ord.size(); i++){
if(ord[i] == x)
return i;
}
return 1e9;
}
int main(){
int n, q, cnt = 0;
cin >> n >> q;
map < int , bool > is;
for(int _ = 0; _ < q; _++){
int x;
cin >> x;
if(is[abs(x)] == true){
cnt++;
is.clear();
}
is[abs(x)] = 1;
}
cout << cnt << "\n";
}
