#include <iostream>
#include <vector>
#include <bitset>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>
#include <cmath>
#include <set>
#include <cstring>
#include <array>
#pragma GCC optimize(2)
//#include <bits/stdc++.h>
#define rep(i,from,to) for(int i=from;i<to;i++)
#define ite2(x,y,arr) for(auto [x,y]:arr)
#define pdd pair<double, double>
#define ite(i,arr) for(auto &i:arr)
#define MID(l,r) int mid=(l+r)>>1
#define ALL(arr) arr.begin(),arr.end()
#define AXY(a,x,y) int x=a.first,y=a.second
#define vc vector
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int,int>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;


#define FTY
double inf = 521.1145314;

namespace G {
#ifdef FTY
    const double eps = 1e-8;
    const double PI = acos(-1);
    struct Point {
        double x, y;
        Point() {
            x = 0, y = 0;
        }
        Point(double x, double y) {
            this->x = x;
            this->y = y;
        }
    };
    bool operator<(Point a, Point b) {
        return a.x < b.x || a.x == b.x && a.y < b.y;
    }
    Point operator +(Point a, Point b) {
        return Point(a.x + b.x, a.y + b.y);
    }
    Point operator -(Point a, Point b) {
        return Point(a.x - b.x, a.y - b.y);
    }
    Point operator *(double a, Point b) {
        return Point(a * b.x, a * b.y);
    }
    Point operator *(Point b, double a) {
        return Point(a * b.x, a * b.y);
    }
    Point operator /(Point b, double a) {
        return Point(b.x / a, b.y / a);
    }
    double len(Point a) {
        return sqrt(a.x * a.x + a.y * a.y);
    }
    double dis(Point a, Point b) {
        return len(a - b);
    }
    bool operator ==(Point a, Point b) {
        return dis(a, b) <= eps||a.x==inf||b.x==inf;
    }
    bool operator !=(Point a, Point b) {
        return !(a == b);
    }
    double operator *(Point a, Point b) {
        return a.x * b.x + a.y * b.y;
    }

    double operator ^(Point a, Point b) {
        return a.x * b.y - a.y * b.x;
    }

    double getAngel(double b, double a, double c) {
        return acos((a * a + c * c - b * b) / (2 * a * c));
    }
    double getAngel(Point a, Point b) {
        return acos(a * b / len(a) / len(b));
    }
    Point inter(Point p, Point v, Point q, Point w) {
        if (fabs(v ^ w) <= eps) {
            return { inf,inf };
        }
        Point u = p - q;
        double t = (w ^ u) / (v ^ w);
        return p + t * v;
    }


#endif
}
using namespace G;
#define int ll
const int mod = (int)1e9 + 7;
//template <class T>
//T __gcd(T a, T b) {
//    if (a < b) swap(a, b);
//    return b ? __gcd(b, a % b) : a;
//}
template <class T>
T __lcm(T a, T b) {
    T num = __gcd(a, b);
    return a / num * b;
}
inline int lowbit(int num) { return num & (-num); }
inline int qmi(int a, int b) {
    a %= mod;
    ll res = 1;
    while (b) {
        if (b & 1) res = (ll)res * a % mod;
        a = (ll)a * a % mod;
        b >>= 1;
    }
    return res;
}
int inv(int num) {
    return qmi(num, mod - 2);
}
void solve() {
    int n, m; cin >> n >> m;
    vector<bitset<1024>>f(1024);
    f[0][0] = 1;
    auto g = f;
    vector<int>v(n + 1), w(n + 1);
    for (int i = 1; i <= n; i++)cin >> v[i] >> w[i];
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j < 1024; j++) {
            g[j] |= (f[j ^ w[i]] << v[i]);
        }
        for (int j = 0; j <1024; j++) {
            f[j] |= g[j];
            
        }
    }
    for (int i = 1023; i >= 1; i--) {
        if (f[i][m]) {
            cout << i << "\n";
            return;
        }
    }
    cout << 1 << "\n";
}
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int tc = 1;
    cin >> tc;
    for (int i = 1; i <= tc; i++) {
        solve();
    }
}