#include <bits/stdc++.h>

using namespace std;
#define ll long long
#define int long long
#define inf 10000000000000000
struct node{
    ll sum = 0;
    ll lazy = 0;
};
node it[400005];
void LazyUp(int index, int L, int R){
    if(it[index].lazy == 0 || L >= R){
        return;
    }
    int val = it[index].lazy;
    int sumL = it[2*index].sum;
    int sumR = it[2*index + 1].sum;
    if(sumL < sumR){
        ll temp = min(it[2*index + 1].sum, val);
        it[2*index + 1].lazy += temp;
        it[2*index + 1].sum -= temp;
        val -= temp;
        it[2*index].lazy += val;
        it[2*index].sum -= val;

    }
    else{
        ll temp = min(it[2*index].sum, val);
        it[2*index].lazy += temp;
        it[2*index].sum -= temp;
        val -= temp;
        it[2*index + 1].lazy += val;
        it[2*index +1].sum -= val;

    }
    it[index].lazy = 0;

}
ll a[200005];
void build(int index,int L, int R){
    if(L >= R){
        it[index].sum = a[L];
        it[index].lazy = 0;
        return;

    }
    int mid = (L + R)/2;
    build(2*index, L, mid);
    build(2*index + 1, mid +1 , R);
    it[index].sum = it[2*index].sum + it[2*index + 1].sum;
}
void update(int index , int L, int R, int l, int r, int val){
    if(l > R || L > r){
        return;
    }
    if(l <= L && R <= r){
        it[index].sum -= val;
        it[index].lazy += val;
        LazyUp(index, L, R);
        return;
    }
    LazyUp(index, L, R);
    int mid = (L + R)/2;
    update(2*index, L, mid, l, r, val);
    update(2*index + 1, mid + 1, R, l, r, val);
    it[index].sum = it[2*index].sum + it[2*index + 1].sum;
}
ll get(int index, int L, int R, int l, int r){
    if(l > R || L > r){
        return 0 ;
    }
    LazyUp(index, L, R);
    if(l <= L && R <= r){
         return it[index].sum;
    }
    int mid = (L + R)/2;
    ll left = get(2*index, L, mid, l, r);
    ll right = get(2*index + 1, mid + 1, R, l, r);
    return left + right;
}
void solve(){
    int n, m;
    cin >>n >> m;
    for(int i = 1; i <= n; i++){
        cin >> a[i];
        
    }
    build(1,1 , n);
    ll cur = 0;
    vector<pair<int, int>> recharge(m+ 2);
    for(int i = 1; i <= m; i++){
          cin >> recharge[i].first >> recharge[i].second;
    }
    recharge[m + 1] = {inf, 1};
    for(int i = 1; i <= m+1; i++){
        ll s = recharge[i].first - cur;
        ll sum = get(1, 1, n, 1, n);
        if(sum < s){
            cur += sum;
            break;
        }
        else{
            ll hp = get(1, 1, n, recharge[i].second, recharge[i].second);
            if(hp < s){
                update(1, 1, n, recharge[i].second, recharge[i].second, hp);
                s -= hp;
                hp = 0;
                update(1, 1, n, 1, n, s);

            }
            else{
                update(1, 1, n, recharge[i].second, recharge[i].second, s);
                hp -=  s;
            }
            cur = recharge[i].first;
            update(1, 1, n, recharge[i].second, recharge[i].second, hp -a[i]);
        }
    }
    cout << cur << endl;
    
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int t;
    cin >> t;
    while(t--){
        solve();
    }
    
     
}