#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

#include <atcoder/modint>

using mint = atcoder::modint998244353;

vector<vector<mint>> mat_mul(vector<vector<mint>> a, vector<vector<mint>> b) {
    int n = a.size();
    vector ans(n, vector<mint>(n, 0));
    for (int i = 0; i < n; i++)
        for (int j = 0; j < n; j++)
            for (int k = 0; k < n; k++) {
                ans[i][j] += a[i][k] * b[k][j];
            }
    return ans;
}

vector<vector<mint>> mat_pow(vector<vector<mint>> a, ll b) {
    int n = a.size();
    vector ans(n, vector<mint>(n, 0));
    for (int i = 0; i < n; i++)
        ans[i][i] = 1;
    while (b) {
        if (b % 2)
            ans = mat_mul(ans, a);
        a = mat_mul(a, a);
        b /= 2;
    }

    return ans;
}
int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    int n, m;
    cin >> n >> m;
    vector<vector<int>> g(n);
    rep(i, m) {
        int a, b;
        cin >> a >> b;
        a--;
        b--;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    vector x(n, vector<mint>(n, 0));
    rep(i, n) {
        for (int j : g[i]) {
            x[i][j] = mint(1) / g[i].size();
        }
    }
    ll s, t, a, b;
    cin >> s >> t >> a >> b;
    s--;
    t--;
    a--;
    b--;
    mint ans = 0;

    ans += mat_pow(x, t)[0][a];
    ans *= mat_pow(x, s - t)[a][b];
    ans /= mat_pow(x, s)[0][b];
    cout << ans.val() << endl;
    return 0;
}