#include <bits/stdc++.h>
using namespace std;
//~ #define int int64_t
#define pb push_back
#define emb emplace_back
#define fr first
#define sc second
#define all(x) x.begin(),x.end()
#define sp << " " <<
#define N 1000
#define inf (int)1e9
typedef pair<int,int> ii;
typedef tuple<int,int,int> iii;
void solve(){
int n,m;
cin >> m >> n;
int p[m+1],box[n][2];
for(int i=1;i<=m;i++)
cin >> p[i];
for(int i=0;i<n;i++)
cin >> box[i][0] >> box[i][1];
sort(p+1,p+m+1,greater<int>());
int cost[m+1]={0};
for(int i=1;i<=m;i++)
cost[i]=cost[i-1]+p[i];
int dp[m+1]={0};
for(int i=1;i<=m;i++)
dp[i]=inf;
for(int i=0;i<n;i++){
for(int j=m-1;j>=0;j--){
if(dp[j]==inf) continue;
if(j+box[i][0]>m)
dp[m]=min(dp[m],dp[j]+box[i][1]);
else
dp[j+box[i][0]]=min(dp[j+box[i][0]],dp[j]+box[i][1]);
}
}
int ans=0;
for(int i=1;i<=m;i++)
ans=max(ans,cost[i]-dp[i]);
cout << ans << endl;
}
int32_t main(){
//~ freopen("hopscotch.in","r",stdin);
//~ freopen("hopscotch.out","w",stdout);
cout << fixed << setprecision(0);
ios_base::sync_with_stdio(false);
cin.tie(NULL);cout.tie(NULL);
int test=1;
//~ cin >> test;
while(test--) solve();
}
