#include<iostream>
#include<fstream>
#include<cstring>
#include<vector>

using namespace std;

const int max_n=10e5;
int start,konec,tstart,tend,prib[max_n][2],que[max_n],n,m,a,b,tain,taout;
int head=0,tail=1,next,now;
int ans, mans[max_n];



vector< vector<int> > graph;

vector< vector<int> > grin;

vector< vector<int> > grout;

void BFS(),dop();

void Input()
{

    cin >> n;
    cin >> m;
    graph.resize(n+1);
    grin.resize(n+1);
    grout.resize(n+1);

    for(int i=0;i<m;i++)
    {
        cin >> a;
        cin >> b;

        graph[a].push_back(b);

        cin >> tain >> taout;

        grin[a].push_back(tain);
        grout[a].push_back(taout);
    }

    cin >> start >> konec >> tstart >> tend;


}

void Solution()
{
    for(int i=0;i<n;i++)
        prib[i][0]=(1e6)+1;
prib[start][1]=-1;
    BFS();


}

void Output()
{
    int kol=0;
    cout<<ans;
    //for(int i= ans ;i != -1;i=prib[i][1] )
      //  mans[kol++]=i;

   /* cout<<kol<<"\n";
    for(int i=kol;i>=0;i--)
    {
        cout<<mans[i]<<" ";
    }
    cout<<"\n";*/
}

int main()
{
    Input();
    Solution();
    Output();

    return 0;
}

void BFS()
{

    que[0]=start;
prib[start][0]=tstart;
    while( head < tail )
    {



        if(now == konec && tend >= prib[now][0]) { ans=head ;   return; }

        now=que[head];
        for(int i = 0;i < graph[now].size();i++)
        {
            next=graph[now][i];
          if(prib[now][0] <= grin[now][i] ) {

              if( prib[next][0] > grout[now][i] ){
                  que[tail++] = graph[now][i];
                  prib[next][0] = grout[now][i];
                  prib[next][1] = now;
                  dop();
                  }
              if( prib[graph[next][i]][0] == (1e6)+1){que[tail++]; prib[graph[next][i]][0]=grout[now][i]; prib[graph[next][i]][1]=now;  }
           }
        }
        ///


    head++;
    }
}

void dop()
{
    for(int i=0;i<graph[next].size();i++ )
    {
        if( prib[graph[next][i]][0] ==(1e6)+1  && prib[next][0] <= grin[next][i] ) {
            que[tail++];
            prib[graph[next][i]][1]=next;
            prib[graph[next][i]][0]=grout[next][i];

            }
    }
}