#include<iostream>
#include<algorithm>
using namespace std;
int main() {
long long V, n;
cin >> V;
cin >> n;
int* items = new int[n];
for (int i = 0; i < n; i++) {
cin >> items[i];
}
sort(items, items + n, greater<int>());
int remain = V;
for (int i = 0; i < n; i++) {
if (remain >= items[i]) {
remain -= items[i];
}
}
cout << remain << endl;
return 0;
}