#include <iostream>
#include <vector>
#include <set>
using namespace std;
int n, m, v, u ,k;
vector<pair<int,int>> raspopov_loh_kek_cheburek;
vector<vector<int>> graf;
set<int> bin;
vector<int> gleb_kakaha_azazazaza;

void dfs(int v, int par){
    gleb_kakaha_azazazaza[v] = 1;
    for (int u: graf[v]){
        if (!gleb_kakaha_azazazaza[u]){
            dfs(u,v);
        }
    }
}
int main(){
    cin >> n >> m >> v >> u;
    for (int i = 0; i < m; ++i){
        int left, right;
        cin >> left >> right;
        left--;
        right--;
        raspopov_loh_kek_cheburek.push_back({left, right});
    }
    cin >> k;
    for (int i = 0; i < k; ++i){
        int tmp;
        cin >> tmp;
        bin.insert(tmp - 1);
    }
    for (int i = 0; i < raspopov_loh_kek_cheburek.size(); ++i){
        if (bin.count(raspopov_loh_kek_cheburek[i].first) || bin.count(raspopov_loh_kek_cheburek[i].second)){
            raspopov_loh_kek_cheburek[i] = {-1,-1};
        }
    }
    graf.resize(n);
    for (auto elem: raspopov_loh_kek_cheburek){
        if (elem.first != -1){
            int a = elem.first;
            int b = elem.second;
            graf[a].push_back(b);
            graf[b].push_back(a);
        }
    }
    gleb_kakaha_azazazaza.resize(n);
    dfs(v - 1, 0);
    if (gleb_kakaha_azazazaza[u - 1]){
        cout << "YES";
    }
    else{
        cout << "NO";
    }
}