#include <bits/stdc++.h>
using namespace std;

using i64 = long long;


void solve() {
	int n, m;
	cin >> n >> m;
	vector<array<int, 2>> a(n);
	for (int i = 0; i < n; ++i) {
		cin >> a[i][0] >> a[i][1];
	}
	vector dp(1024, bitset<1024>(0));
	dp[0][0] = 1;
	for (auto &[v, w] : a) {
		for (int i = 0; i < (1 << 10); ++i) {
			dp[i] |= (dp[i ^ w] << v);
		} 
	}
	for (int i = (1 << 10) - 1; i > 0; --i) {
		if (dp[i][m]) {
			cout << i << '\n';
			return;
		}
	}
	cout << 1 << '\n';
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    cin >> t;
    while(t--) {
        solve();
    }
    return 0;
}