#include <bits/stdc++.h>
using namespace std;
using int64 = long long;
const long long INF = (long long)1e16;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int a, b;
cin >> a >> b;
vector<long long> t(a+1), prefix(a+1, 0);
for (int i = 1; i <= a; ++i) cin >> t[i];
sort(t.begin()+1, t.begin()+a+1, greater<long long>());
for (int i = 1; i <= a; ++i) prefix[i] = prefix[i-1] + t[i];
vector<pair<int,int>> z(b+1);
for (int i = 1; i <= b; ++i) {
cin >> z[i].first >> z[i].second;
if (z[i].first > a) z[i].first = a;
}
vector<long long> dp_prev(a+2, INF), dp_cur(a+2, INF);
dp_prev[0] = 0;
for (int i = 1; i <= b; ++i) {
int w = z[i].first;
int c = z[i].second;
for (int j = 0; j <= a; ++j) dp_cur[j] = dp_prev[j];
for (int j = w; j <= a; ++j) {
dp_cur[j] = min(dp_cur[j], dp_prev[j - w] + c);
}
dp_cur[a+1] = INF;
for (int j = a; j >= 0; --j) {
dp_cur[j] = min(dp_cur[j], dp_cur[j+1]);
}
swap(dp_prev, dp_cur);
fill(dp_cur.begin(), dp_cur.end(), INF);
}
long long ans = 0;
for (int i = 1; i <= a; ++i) {
if (dp_prev[i] < INF) ans = max(ans, prefix[i] - dp_prev[i]);
}
cout << ans << '\n';
return 0;
}
