#include <bits/stdc++.h>

using namespace std;
ifstream in("easygraph.in");
ofstream out("easygraph.out");
const int nmax=16e3;
int n, m;
int value[nmax+1], dp[nmax+1];
vector <int> graph[nmax+1];
bitset <nmax+1> vis;
void dfs(int start)
{
    if(vis[start]==0)
    {
        vis[start]=1;
        for(int i=0; i<graph[start].size(); i++)
        {
            int copil=graph[start][i];
            if(vis[copil]==0)
            {
                dfs(copil);
                dp[start]=max(dp[start], dp[copil]);
            }
        }
        dp[start]+=value[start];
    }
}
int main()
{
    int t;
    in>>t;
    while(t)
    {
        t--;
        in>>n>>m;
        vis.reset();
        for(int i=1; i<=n; i++)
        {
            in>>value[i];
            dp[i]=0;
            graph[i].clear();
        }
        int x, y;
        for(int i=1; i<=m; i++)
        {
            in>>x>>y;
            graph[x].push_back(y);
        }
        dfs(1);
        int rez=-1e9;
        for(int i=1; i<=n; i++)
        {
            rez=max(rez, dp[i]);
        }
        out<<rez<<'\n';
    }
}