import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.NoSuchElementException;
import java.util.PriorityQueue;

class Edge{
	int dst;
	long cost;
	
	public Edge(int dst,long cost) {
		this.dst=dst;
		this.cost=cost;
	}
}

public class Main {
	public static void main(String[] args) throws FileNotFoundException {
		long t = System.currentTimeMillis();
		new Main().run();
		System.err.println(System.currentTimeMillis() - t);
	}
	
	long[] shortest_path(int src,ArrayList<Edge>[] g) {
		long[] dp=new long[g.length];
		long INF=Long.MAX_VALUE/3;
		Arrays.fill(dp, INF);
		dp[src]=0;
		class S implements Comparable<S>{
			int v;
			long d;
			
			public S(int v,long d) {
				this.v=v;
				this.d=d;
			}
			
			public int compareTo(S o) {
				return Long.compare(d, o.d);
			};
		}
		PriorityQueue<S> pq=new PriorityQueue<>();
		pq.add(new S(src, 0));
		while(!pq.isEmpty()) {
			S s=pq.poll();
			if(dp[s.v]<s.d)continue;
			for(Edge e:g[s.v]) {
				if(dp[s.v]+e.cost<dp[e.dst]) {
					dp[e.dst]=dp[s.v]+e.cost;
					pq.add(new S(e.dst,dp[e.dst]));
				}
			}
		}
		return dp;
	}
	
	void run() {
		FastScanner sc = new FastScanner();
		int N=sc.nextInt();
		int M=sc.nextInt();
		int P=sc.nextInt()-1;
		int Q=sc.nextInt()-1;
		long T=sc.nextLong();
		ArrayList<Edge>[] g=new ArrayList[N];
		for(int i=0;i<N;++i)g[i]=new ArrayList<>();
		for(int i=0;i<M;++i) {
			int a=sc.nextInt()-1;
			int b=sc.nextInt()-1;
			long c=sc.nextLong();
			g[a].add(new Edge(b,c));
			g[b].add(new Edge(a,c));
		}
		long[] v0=shortest_path(0, g);
		long[] vp=shortest_path(P, g);
		long[] vq=shortest_path(Q, g);
		long INF=Long.MAX_VALUE/3;
		long ans=-INF;
		if(v0[P]+v0[Q]+vp[Q]<=T)ans=T;
		for(int i=0;i<N;++i) {
			if(2*(v0[i]+Math.max(vp[i], vq[i]))<=T) {
				ans=Math.max(ans, T-2*Math.max(vp[i], vq[i]));
			}
		}
		System.out.println(ans==-INF?-1:ans);
	}
	
	static void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}

}
	
	
class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
    private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
    private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;}
    public boolean hasNext() { skipUnprintable(); return hasNextByte();}
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    
    public int nextInt() {
    	return (int)nextLong();
    }
}