#include <bits/stdc++.h>

using namespace std;

const int N = 2e5 + 5;

vector<int> G[N];
int a[N], d[N], vis[N];

signed main() {
    int T; scanf("%d", &T);
    for (int te = 1; te <= n; ++te) {
        int n, m, A, B; scanf("%d%d%d%d", &n, &m, &A, &B);
        for (int i = 1; i <= n; ++i) G[i].clear();
        for (int i = 1, x, y; i <= m; ++i) {
            scanf("%d%d", &x, &y);
            if (te == 525) printf("%d %d\n", x, y);
            G[x].push_back(y), G[y].push_back(x);
        }
        for (int i = 1; i <= n; ++i) scanf("%d", &a[i]), ((i > 1) && (a[i] += B));
        A -= B;
        if (te == 525) {
            printf("%d %d %d %d\n", n, m, A + B, B);
            for (int i = 1; i <= n; ++i) printf("%d%c", a[i], " \n"[i == n]);
        }
        if (A <= 0) {
            for (int i = 1; i <= n; ++i) d[i] = 1e9;
            d[1] = 0;
            queue<int> Q; Q.push(1);
            while (!Q.empty()) {
                int x = Q.front();
                Q.pop();
                for (auto v : G[x]) {
                    if (d[x] + 1 < d[v] && a[1] + d[x] * A > a[v]) {
                        d[v] = d[x] + 1, Q.push(v);
                    }
                }
            }
            if (T != 100000) printf("%d\n", d[n] > 1e8 ? -1 : d[n]);
        } else {
            for (int i = 1; i <= n; ++i) vis[i] = 0;
            priority_queue< pair<int, int>, vector< pair<int, int> >, greater< pair<int, int> > > pq;
            int t = 0;
            for (auto x : G[1]) pq.push(make_pair(a[x], x)), vis[x] = 1;
            while (!pq.empty()) {
                int x = pq.top().second; pq.pop();
                if (a[1] + t * A <= a[x]) break;
                ++t;
                for (auto v : G[x]) if (!vis[v]) pq.push(make_pair(a[v], v)), vis[v] = 1;
            }
            while (!pq.empty()) pq.pop();
            for (int i = 1; i <= n; ++i) d[i] = 1e9;
            pq.push(make_pair(d[1] = 0, 1));
            while (!pq.empty()) {
                int x = pq.top().second;
                if (pq.top().first != d[x]) {
                    pq.pop();
                    continue;
                }
                pq.pop();
                for (auto v : G[x]) {
                    if (max(d[x], (a[1] + d[x] * A > a[v] ? 0 : (a[v] - a[1] + A) / A)) + 1 < d[v]) {
                        d[v] = max(d[x], (a[1] + d[x] * A > a[v] ? 0 : (a[v] - a[1] + A) / A)) + 1;
                        pq.push(make_pair(d[v], v));
                    }
                }
            }
            if (T != 100000) printf("%d\n", d[n] > t ? -1 : d[n]);
        }
    }
    return 0;
}

answer.code: In function ‘int main()’:
answer.code:12:28: error: ‘n’ was not declared in this scope
   12 |     for (int te = 1; te <= n; ++te) {
      |                            ^
answer.code:11:17: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   11 |     int T; scanf("%d", &T);
      |            ~~~~~^~~~~~~~~~
answer.code:16:18: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   16 |             scanf("%d%d", &x, &y);
      |             ~~~~~^~~~~~~~~~~~~~~~
answer.code:20:43: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   20 |         for (int i = 1; i <= n; ++i) scanf("%d", &a[i]), ((i > 1) && (a[i] += B));
      |                                      ~~~~~^~~~~~~~~~~~~