#include <bits/stdc++.h>
#define ll long long
#define Orz ios::sync_with_stdio(0),cin.tie(0)
#define N 3005
#define FOR(i,n) for(int i=0;i<n;i++)
#define pii pair<int,int>
#define pid pair<int,double>
#define pdi pair<double,int>
using namespace std;
int n,m,s1,e1,w1,s2,e2,w2,dis[N][N];
bool visit[N];
vector<int> edge[N];

int main(){
    cin>>n>>m;
    for(int i=0;i<m;i++){
        int a,b;cin>>a>>b;
        edge[a].push_back(b);
        edge[b].push_back(a);
    }
    cin>>s1>>e1>>w1>>s2>>e2>>w2;
    memset(dis,0x3f3f3f3f,sizeof(dis));
    
    for(int i=1;i<=n;i++){
        memset(visit,0,sizeof(visit));
        queue<int>que;
        que.push(i);
        visit[i] = 1;
        dis[i][i] = 0;
        while(!que.empty()){
            int cur = que.front();
            que.pop();
            for(auto j:edge[cur]){
                if(visit[j])continue;
                dis[i][j] = dis[i][cur]+1;
                visit[j] = 1;
                que.push(j);
            }
        }
    }
    if(dis[s1][e1]>w1||dis[s2][e2]>w2){
        cout<<-1<<endl;
        return 0;
    }
    int ans = dis[s1][e1]+dis[s2][e2];
    
//    for(int i=1;i<=n;i++){
//        for(int j=1;j<=n;j++){
//            if(dis[i][j]!=dis[j][i])cout<<1<<endl;
//        }
//        cout<<endl;
//    }
    
    //O(n^2)枚舉所有共同邊
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            if(dis[s1][i]+dis[i][j]+dis[j][e1]<=w1&&dis[s2][i]+dis[i][j]+dis[j][e2]<=w2)
                ans = min(ans,dis[s1][i]+dis[i][j]+dis[j][e1]+dis[s2][i]+dis[j][e2]);
            if(dis[s1][i]+dis[i][j]+dis[j][e1]<=w1&&dis[e2][i]+dis[i][j]+dis[j][s2]<=w2)
                ans=min(ans,dis[s1][i]+dis[i][j]+dis[j][e1]+dis[e2][i]+dis[j][s2]);
            
        }
    }
    cout<<m-ans<<endl;
}