#include <iostream>
#include <algorithm>
#include <set>
using namespace std;
#define X first
#define Y second
#define INF 0x7f7f7f7f
int arr[10005], dp[10005];
pair<int, int> box[10005];
multiset<int> ms;
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
int m, n;
cin >> m >> n;
for(int i = 0; i < m; i++)
cin >> arr[i];
for(int i = 0; i < n; i++)
cin >> box[i].X >> box[i].Y;
sort(arr, arr+m, greater<>());
fill(dp+1, dp+m+1, INF);
for(int i = 0; i < n; i++)
{
ms.clear();
for(int j = 0; j <= box[i].X; j++)
if(m-j >= 0)
ms.insert(dp[m-j]);
for(int j = m; j >= 0; j--)
{
int temp = dp[j];
dp[j] = min(dp[j], *ms.begin() + box[i].Y);
ms.erase(ms.find(temp));
if(j-box[i].X-1 >= 0)
ms.insert(dp[j-box[i].X-1]);
}
}
int ans = 0, sum = 0;
for(int i = 0; i < m; i++)
{
sum += arr[i];
ans = max(ans, sum-dp[i+1]);
}
cout << ans << '\n';
}
