#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
int N,M,K,S,T;
int a[2<<17],b[2<<17],c[2<<17];
long dist[2<<17];
vector<pair<int,long> >X[2<<17];
main()
{
	cin>>N>>M>>K>>S>>T;
	X[N-1].push_back(make_pair(T,-M-1));
	dist[M+1]=1e18;
	for(int i=0;i++<M;)
	{
		dist[i]=1e18;
		cin>>a[i]>>b[i]>>c[i];
		a[i]--;
		X[a[i]].push_back(make_pair(b[i],-i));
	}
	X[0].push_back(make_pair(S,0));
	for(int i=0;i<N;i++)
	{
		sort(X[i].begin(),X[i].end());
		long now=1e18,pre=0;
		int n=X[i].size();
		for(int j=0;j<n;j++)
		{
			now+=X[i][j].first-pre;
			pre=X[i][j].first;
			if(X[i][j].second>=0)
			{
				now=min(now,X[i][j].second);
			}
			else
			{
				int id=-X[i][j].second;
				dist[id]=min(dist[id],now);
			}
		}
		now=1e18,pre=1e9;
		for(int j=n;j--;)
		{
			now+=pre-X[i][j].first;
			pre=X[i][j].first;
			if(X[i][j].second>=0)
			{
				now=min(now,X[i][j].second);
			}
			else
			{
				int id=-X[i][j].second;
				dist[id]=min(dist[id],now);
			}
		}
		if(i+1<N)
		{
			for(int j=0;j<n;j++)
			{
				if(X[i][j].second<0)
				{
					int id=-X[i][j].second;
					X[i+1].push_back(make_pair(c[id],dist[id]));
				}
			}
		}
	}
	long ans=dist[M+1];
	cout<<(ans<1e18?ans:-1)<<endl;
}