#include<deque>
#include<queue>
#include<vector>
#include<algorithm>
#include<iostream>
#include<set>
#include<cmath>
#include<tuple>
#include<string>
#include<chrono>
#include<functional>
#include<iterator>
#include<random>
#include<unordered_set>
#include<unordered_map>
#include<array>
#include<map>
#include<bitset>
#include<iomanip>
using namespace std;
typedef long long int llint;
typedef long double lldo;
#define mp make_pair
#define mt make_tuple
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define fir first
#define sec second
#define res resize
#define ins insert
#define era erase
//ios::sync_with_stdio(false);
//std::cin.tie(0);
//<< setprecision(20)
const int mod=1e9+7;
const llint big=1e15+100;
const long double pai=3.141592653589793238462643383279502884197;
const long double ena=2.71828182845904523536;
const long double eps=1e-7;
template <class T,class U>void mineq(T& a,U b){if(a>b){a=b;}}
template <class T,class U>void maxeq(T& a,U b){if(a<b){a=b;}}
template <class T> void soun(T& ar)
{sort(ar.begin(),ar.end());ar.erase(unique(ar.begin(),ar.end()),ar.end());}
llint gcd(llint a,llint b){if(a%b==0){return b;}else return gcd(b,a%b);}
llint lcm(llint a,llint b){return a/gcd(a,b)*b;}
int main(void){
	llint i,n,m,k,s,t;cin>>n>>m>>k>>s>>t;
	vector<vector<tuple<llint,int,llint>>>go(n+1);//クエリ全般
	for(i=0;i<m;i++){
		int a,b,c;cin>>a>>b>>c;a--;
		go[a].pub(mt(b,0,c));//b->c 
	}
	go[n-1].pub(mt(t,0,0));//t->0
	for(i=0;i<n-1;i++){if(go[i].size()==0){cout<<-1<<endl;return 0;}}
	vector<pair<llint,llint>> now;//場所
	go[0].pub(mt(s,1,0LL));//到着側
	for(i=0;i<n;i++){
		sort(go[i].begin(),go[i].end());//尺取り
		llint hiro=big;//疲労
		llint mae=0;//前の場所
		for(auto it:go[i]){
			hiro+=get<0>(it)-mae;
			mae=get<0>(it);
			if(get<1>(it)==0){go[i+1].pub(mt(get<2>(it),1,hiro));}
			else{mineq(hiro,get<2>(it));}
		}
		reverse(go[i].begin(),go[i].end());//逆
		hiro=big,mae=big;
		for(auto it:go[i]){
			hiro-=get<0>(it)-mae;
			mae=get<0>(it);
			if(get<1>(it)==0){go[i+1].pub(mt(get<2>(it),1,hiro));}
			else{mineq(hiro,get<2>(it));}
		}
	}
	llint ans=big;
	for(auto it:go[n]){mineq(ans,get<2>(it));}
	cout<<ans<<endl;
	return 0;
}