Sunnydale

#include <bits/stdc++.h>
using namespace std;

int main()
{
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    int n,m,h,s;

    cin>>n>>m>>h>>s;

    vector<vector<int>> g(n, vector<int>(n,0));

    for(int i=0;i<m;i++)
    {
        int a,b,c;
        cin>>a>>b>>c;
        g[a-1][b-1] = c;
        g[b-1][a-1] = c;
    }


    int partenza = h-1;
    int indiceMin;
    int min = 50001;
    int ans = 0;

    if(h == s)
    {
        cout<<ans<<endl;
        return 0;
    }

    for(int i=0;i<n;i++)
    {
        if(g[partenza][i] == 0 || g[partenza][i] == -1)
            continue;

        if(partenza == s-1)
        {
            cout<<ans<<endl;
            return 0;
        }

        if(g[partenza][i] < min)
        {
            min = g[partenza][i];
            indiceMin = i;
        }

        if(i == n-1)
        {
            min = 50001;
            i=-1;
            ans++;
            partenza = indiceMin;
        }

    }


    cout<<-1<<endl;

}