#include <bits/stdc++.h>
using namespace std;
#if __has_include("all.hpp")
#include "all.hpp"
#else
#include <atcoder/all>
#endif
using namespace atcoder;
using mint=modint998244353;
int main(void){
    int n,m;
    cin>>n>>m;
    vector<vector<int>>v(n);
    for(int i=0;i<m;i++){
        int a,b;
        cin>>a>>b;
        a--,b--;
        v[b].push_back(a);
        v[a].push_back(b);
    }
    auto ml = [&](vector<vector<mint>>A,vector<vector<mint>>B){
        vector<vector<mint>>tmp(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++)tmp[i][j]+=A[k][i]*B[j][k];
        return tmp;
    };
    vector<vector<vector<mint>>>doub(62,vector<vector<mint>>(n,vector<mint>(n,0)));
    for(int i=0;i<n;i++){
        if(v[i].size()==0)continue;
        for(int j=0;j<v[i].size();j++){
            doub[0][i][v[i][j]]=1/(mint)(v[i].size());
        }
    }
    for(int i=1;i<62;i++){
        doub[i]=ml(doub[i-1],doub[i-1]);
    }
    long long a,b,s,t;
    cin>>s>>t>>a>>b;
    a--,b--;
    auto calc = [&](long long startt,long long goalt,long long startp,long long goalp){
        vector<vector<mint>>tmp(n,vector<mint>(n,0));
        for(int i=0;i<n;i++)tmp[i][i]=1;
        long long cnt=goalt-startt;
        for(long long i=61;i>=0;i--){
            if((1<<i)&cnt){
                tmp=ml(tmp,doub[i]);
            }
        }
        return tmp[startp][goalp];
    };
    cout<<(calc(1,t,0,b)*calc(t,s,b,a)/calc(1,s,0,a)).val()<<endl;
    return 0;
}