export {};
const input = require("fs").readFileSync(0).toString().trim().split("\n");
const T: number = Number(input[0]);
let idx: number = 1;

let res: number[] = [];

for(let t=0; t<T; t++) {
    const [N, K]: number[] = input[idx++].split(" ").map(Number);
    const line1: number[] = input[idx++].split(" ").map(Number);
    const build_time: number[] = Array.from({length: N+1}, (_,i) => i===0 ? 0 : line1[i-1]);

    let prev_build: number[][] = Array.from({length: N+1}, () => []);
    for(let k=0; k<K; k++) {
        const [X, Y]: number[] = input[idx++].split(" ").map(Number);
        prev_build[Y].push(X);
    }

    let dp: number[] = new Array(N+1).fill(-1);

    const solve = (target : number): number => {
        if(dp[target] === -1) {
            let max_build_time: number = 0;
            for(let prev of prev_build[target]) {
                max_build_time = Math.max(max_build_time, solve(prev));
            }

            dp[target] = build_time[target] + max_build_time;
        }
        
        return dp[target];
    };

    const W: number = Number(input[idx++]);
    res.push(solve(W));
}

console.log(res.join("\n"));