#include <bits/stdc++.h>

#define LL long long
#define ull unsigned long long
#define F(i, j, k) for (int i = j; i <= k; ++i)
#define DF(i, j, k) for (int i = j; i >= k; --i)

using namespace std;

template <typename T> inline void read(T &n) {
    T w = 1;
    n = 0;
    char ch = getchar();
    while (!isdigit(ch) && ch != EOF) {
        if (ch == '-') w = -1;
        ch = getchar();
    }
    while (isdigit(ch) && ch != EOF) {
        n = (n << 3) + (n << 1) + (ch & 15);
        ch = getchar();
    }
    n *= w;
}

template <typename T> inline void write(T x) {
    T l = 0;
    ull y = 0;
    if (!x) { putchar(48); return; }
    if (x < 0) { x = -x; putchar('-'); }
    while (x) { y = y * 10 + x % 10; x /= 10; ++l; }
    while (l) { putchar(y % 10 + 48); y /= 10; --l; }
}

template <typename T> inline void writes(T x) {
    write(x);
    putchar(' ');
}

template <typename T> inline void writeln(T x) {
    write(x);
    puts("");
}

template <typename T> inline void checkmax(T &a, T b) { a = a > b ? a : b; }

template <typename T> inline void checkmin(T &a, T b) { a = a < b ? a : b; }

inline void solve() {
    int n, k; read(n); read(k);
    LL sum = 0;
    LL sum1 = 0;
    F(i, 1, n) {
        int x; read(x);
        sum += x;
        if (x == 1) ++sum1;
    }
    F(i, 1, n - 1) {
        int x, y;
        read(x); read(y);
    }
    if (k & 1) cout << min(sum1, sum / k) << endl;
    else cout << (sum / k) << endl;
}

int main() {
    //freopen(".in", "r", stdin);
    //freopen(".out", "w", stdout);
    int t; read(t);
    while (t--) solve();
    return 0;
}