#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;

#define pb push_back
const int MAXN = 2 * 1e5 + 10;

int n, m, k[MAXN], sum = 0;
vector<int> discount[MAXN];

int lastDis[MAXN * 3];
bool check(int d){
    fill(lastDis, lastDis + d, 0);
    for(int i = 1; i <=n; i++){
        if(discount[i].size()==0)continue;
        int l = 0, r = discount[i].size(), m;
        while(r-l > 1){
            m = (l+r)/2;
            if(discount[i][m] <= d)l = m;
            else r = m;
        }
        lastDis[discount[i][l]] += k[i];
    }

    int money = 0, left = sum;
    for(int i = 1; i <= d; i++){
        money++;
        if(money <= lastDis[i]){
            left -= money;
            money = 0;
        }else{
            left -= lastDis[i];
            money -= lastDis[i];
        }
    }
    if(money >= 2 * left)return true;
    return false;
}

int main(){
    cin>>n>>m;
    for(int i = 1; i <= n; i++){
        cin>>k[i];
        sum += k[i];
    }
    int ti, di;
    for(int i = 0; i < m; i++){
        cin>>di>>ti;
        discount[ti].pb(di);
    }
    for(int i = 1; i <= n; i++){
        sort(discount[i].begin(), discount[i].end());
    }
    int l = sum, r = 2 * sum, m;
    while(l != r){
        m = (l + r) / 2;
        if(check(m))r = m;
        else l = m + 1;
    }

    cout<<l;

    return 0;
}