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

int INF = 1000000000;
int teskes, m, s;
int a[50], b[50];

int dp[44][311][311];
int cc(int ke, int ca, int cb) {
    if(dp[ke][ca][cb] != -1) {
        return dp[ke][ca][cb];
    }

    if(ca == 0 && cb == 0) {
        return 0;
    }

    if(ke >= m || ca < 0 || cb < 0) {
        return INF;
    }

    int pakai0 = cc(ke, ca-a[ke], cb-b[ke]) + 1;
    int pakai1 = cc(ke+1, ca-a[ke], cb-b[ke]) + 1;
    int pakai2 = cc(ke+1, ca, cb);
    return dp[ke][ca][cb] = min(pakai0, min(pakai1, pakai2));
}

int main() {
    scanf("%d", &teskes);
    while(teskes--) {
        scanf("%d%d", &m, &s);
        for(int i = 0; i < m; i++) {
            scanf("%d %d", &a[i], &b[i]);
        }

        int ans = INF;
        for(int i = 1; i <= s; i++) {
            for(int j = 1; j <= s; j++) {
                if(i * i + j * j == s * s) {
                    memset(dp, -1, sizeof dp);
                    ans = min(ans, cc(0, i, j));
                }
            }
        }
        if(ans >= INF) {
            printf("not possible\n");
        } else {
            printf("%d\n", ans);
        }
    }
    return 0;
}