#include<bits/stdc++.h>
#define int long long
using namespace std;
ifstream fin("NPH.in");
ofstream fout("NPH.out");
auto mread = [](){
    int x;
    fin >> x;
    return x;
};
int C(int n, int m){
    int ans = 1;
    for(int i = n; i >= n - m + 1; i --)
    ans *= i;
    for(int i = 1; i <= m; i ++)
    ans /= i;
    return ans;
}
signed main(){
    int t = mread();
    while(t --){
        int n = mread(), k = mread();
        int a[n + 5];
        for(int i = 1; i <= n; i ++)
        a[i] = mread();
        if(n == 1){
            fout << a[1] * k << "\n";
            continue;
        }
        {
            int e = 1;
            for(int i = 1; i <= n; i ++){
                if(a[i] != 1)
                e = 0;
            }
            if(e){
                int sum = 0;
                for(int i = 1; 1; i ++){
                    sum += C(i + n - 1, n - 1);
                    if(sum >= k){
                        fout << i << "\n";
                        break;
                    }
                }
                continue;
            }
        }
        if(k <= 100000){
            vector<int> f;
            f.push_back(1);
            int sum = 0;
            for(int i = 1; 1; i ++){
                int ans = 0;
                for(int j = 1; j <= n; j ++){
                    if(i - a[j] >= 0)
                    ans += f[i - a[j]];
                }
                sum += ans;
                f.push_back(ans);
//                printf("*** %lld\n", ans);
                if(sum >= k){
                    fout << i << "\n";
                    break;
                }
            }
            continue;
        }
    }
}