#include <bits/stdc++.h>
using namespace std;
int main(){
    set<int> I,reach;
    int N,M,S,G,U,input;
    cin>>N>>M>>S>>G;
    int E[M][2];
    vector<vector<int>> C(N,vector<int>(N));
    queue<int> Q;
    Q.push(S-1);
    for(int i=0;i<M;++i){
        cin>>E[i][0]>>E[i][1];
    }
    cin>>U;
    for(int i=0;i<U;++i){
        cin>>input;
        I.insert(input);
    }
    for(int i=0;i<M;++i){
        if(!I.count(E[i][1])){
            C[E[i][0]-1].emplace_back(E[i][1]-1);
        }
    }
    while(!Q.empty()){
        reach.insert(Q.front());
        for(int i:C[Q.front()]){
            if(!reach.count(i)){
                Q.push(i);
            }
        }
        Q.pop();
    }
    cout<<(reach.count(G-1)?"Yes":"No")<<endl;
}