#include <bits/stdc++.h>
using namespace std;
#define int long long
#define INF (int)1e18
#define f first
#define s second
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
void Solve()
{
int n, m; cin >> m >> n;
vector <int> dp(m + 1, INF);
dp[0] = 0;
vector <int> p(m);
for (auto &x : p) cin >> x;
sort(p.begin(), p.end(), greater<int>());
while (n--){
int c, e; cin >> c >> e;
for (int j = m; j >= 1; j--){
int go = max(0LL, j - c);
dp[j] = min(dp[j], dp[go] + e);
}
}
int curr = 0;
int ans = 0;
int cnt = 0;
for (auto x : p){
curr += x;
cnt++;
// cout << curr << " " << cnt << " " << dp[cnt] << "\n";
ans = max(ans, curr - dp[cnt]);
}
cout << ans << "\n";
}
int32_t main()
{
auto begin = std::chrono::high_resolution_clock::now();
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
for(int i = 1; i <= t; i++)
{
//cout << "Case #" << i << ": ";
Solve();
}
auto end = std::chrono::high_resolution_clock::now();
auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n";
return 0;
}
