#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main()
{
    int t;
    cin >> t;
    while (t--)
    {
        int n, m;
        cin >> n >> m;
        int a[n + 10];
        int sum = 0;
        for (int i = 1; i <= n; i++)
            cin >> a[i], sum += a[i];
        int lasp = 1, lassum = 0, lasdis = 0; // 上一个站点和总残留和上一战的位置
        int ans = 0;
        int s[m+10],nd[m+10];
        for(int i=0;i<m;i++)cin>>nd[i]>>s[i];
        for (int i = 0; i < m; i++)
        {
            int site, nowdis;
            site=s[i],nowdis=nd[i];
            int dis = nowdis - lasdis;
            if (dis + lassum > sum)
                break;
            ans = nowdis;
            if (dis + (site == lasp?0:lassum)>a[site])
                lassum = dis + lassum - a[site];
            else
                lassum = 0;
            lasp = site;
            lasdis = nowdis;
        }
        ans += sum - lassum;
        cout << ans << endl;
    }
}