#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <set>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <cstdio>
#include <cstring>
#include <iterator>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
#include <fstream>
#include <iomanip>
#include <cassert>
#include <utility>
#include <memory>
#include <functional>
#include <deque>
#include <cctype>
#include <ctime>
#include <numeric>
#include <list>
#include <iomanip>

#if __cplusplus >= 201103L
#include <array>
#include <tuple>
#include <initializer_list>
#include <forward_list>

#define cauto const auto&
#else

#endif

using namespace std;


typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vint;
typedef vector<vector<int> > vvint;
typedef vector<long long> vll;
typedef vector<vector<long long> > vvll;

#define VV(T) vector<vector< T > >

template <class T>
void initvv(vector<vector<T> > &v, int a, int b, const T &t = T()){
    v.assign(a, vector<T>(b, t));
}

template <class F, class T>
void convert(const F &f, T &t){
    stringstream ss;
    ss << f;
    ss >> t;
}

#define GET_MACRO(_1, _2, _3, NAME, ...) NAME
#define _rep(i,n) _rep2((i),0,(n))
#define _rep2(i,a,b) for(int i=(a);i<(b);++i)
#define rep(...) GET_MACRO(__VA_ARGS__, _rep2, _rep)(__VA_ARGS__)
#define ALL(v) (v).begin(),(v).end()
#define PB push_back
#define fi first
#define se second
#define mkp make_pair
#define DEBUG
#ifdef DEBUG
#define dump(x)  cout << #x << " = " << (x) << endl;
#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#else
#define dump(x) 
#define debug(x) 
#endif

#define MOD 1000000007LL
#define EPS 1e-8
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
#define maxs(x,y) x=max(x,y)
#define mins(x,y) x=min(x,y)

void mainmain(){
	int n,m,K,S,T;
	cin>>n>>m>>K>>S>>T;
	VV(pii) vv(n);
	rep(i,m){
		int a,b,c;
		cin>>a>>b>>c;
		a--;
		vv[a].PB(pii(b,c));
	}
	vv[n-1].PB(pii(T,T));
	map<int,ll> ma;
	ma[S] = 0;
	rep(i,n){
		for(auto x: vv[i]){
			if(ma.count(x.fi)) continue;
			ma[x.fi] = INFL;	
		}
		int p = 0;
		ll val = INFL;
		for(auto &x: ma){
			if(x.se > x.fi - p + val){
				x.se = x.fi - p + val;
			}
			else{
				p = x.fi;
				val = x.se;
			}
		}
		p = K+1;
		val = INFL;
		for(auto i = ma.rbegin(); i != ma.rend(); ++i){
			auto& x = (*i);
			if(x.se > p - x.fi + val){
				x.se = p - x.fi + val;
			}
			else{
				p = x.fi;
				val = x.se;
			}
		}
		// cout<<"count "<<ma.count(3)<<endl;
		// cout<<ma[3]<<endl;
		map<int,ll> next;
		for(auto x: vv[i]){
			if(next.count(x.se)){
				mins(next[x.se], ma[x.fi]);
			}
			else{
				next[x.se] = ma[x.fi];
			}
		}
		ma = next;
	}
	cout<<(ma[T]==INFL?-1:ma[T])<<endl;
}


signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout<<fixed<<setprecision(20);
    mainmain();
}