# include "bits/stdc++.h" using namespace std; using LL = long long; using ULL = unsigned long long; const double PI = acos(-1); templateconstexpr T INF() { return ::std::numeric_limits::max(); } templateconstexpr T HINF() { return INF() / 2; } template T_char TL(T_char cX) { return tolower(cX); }; template T_char TU(T_char cX) { return toupper(cX); }; const int vy[] = { -1, -1, -1, 0, 1, 1, 1, 0 }, vx[] = { -1, 0, 1, 1, 1, 0, -1, -1 }; const int dx[4] = { 0,1,0,-1 }, dy[4] = { 1,0,-1,0 }; int popcnt(unsigned long long n) { int cnt = 0; for (int i = 0; i < 64; i++)if ((n >> i) & 1)cnt++; return cnt; } int d_sum(LL n) { int ret = 0; while (n > 0) { ret += n % 10; n /= 10; }return ret; } int d_cnt(LL n) { int ret = 0; while (n > 0) { ret++; n /= 10; }return ret; } LL gcd(LL a, LL b) { if (b == 0)return a; return gcd(b, a%b); }; LL lcm(LL a, LL b) { LL g = gcd(a, b); return a / g*b; }; # define ALL(qpqpq) (qpqpq).begin(),(qpqpq).end() # define UNIQUE(wpwpw) sort(ALL((wpwpw)));(wpwpw).erase(unique(ALL((wpwpw))),(wpwpw).end()) # define LOWER(epepe) transform(ALL((epepe)),(epepe).begin(),TL) # define UPPER(rprpr) transform(ALL((rprpr)),(rprpr).begin(),TU) # define FOR(i,tptpt,ypypy) for(LL i=(tptpt);i<(ypypy);i++) # define REP(i,upupu) FOR(i,0,upupu) # define INIT std::ios::sync_with_stdio(false);std::cin.tie(0) struct edge { LL to, cost; }; int start; LL d[404040]; //距離 vector vec[404040]; void dijkstra() { for (int i = 0; i < 404040; i++)d[i] = HINF(); priority_queue, std::vector>, std::greater>> pq; d[start] = 0; pq.push(make_pair(d[start], start));//cost,to while (!pq.empty()) { pair p = pq.top(); pq.pop(); int i = p.second; if (d[i] < p.first)continue; for (int k = 0; k < (int)vec[i].size(); k++) { edge e = vec[i][k]; if (d[e.to] <= d[i] + e.cost)continue; d[e.to] = d[i] + e.cost; pq.push(make_pair(d[e.to], e.to)); } } } int n, m, k, s, t; int a[202020], b[202020], c[202020]; vector v[202020]; map mp[202020]; int main(){ INIT; cin >> n >> m >> k >> s >> t; s--, t--; int idx = 0; mp[0][s] = idx++; v[0].emplace_back(s); mp[n - 1][t] = idx++; v[n - 1].emplace_back(t); REP(i, m){ cin >> a[i] >> b[i] >> c[i]; a[i]--, b[i]--, c[i]--; v[a[i]].emplace_back(b[i]); v[a[i] + 1].emplace_back(c[i]); if(!mp[a[i]].count(b[i]))mp[a[i]][b[i]] = idx++; if(!mp[a[i] + 1].count(c[i]))mp[a[i] + 1][c[i]] = idx++; vec[mp[a[i]][b[i]]].emplace_back(edge{mp[a[i] + 1][c[i]], 0}); } REP(i, n){ sort(ALL(v[i])); UNIQUE(v[i]); REP(j, (int)v[i].size() - 1){ vec[mp[i][v[i][j + 1]]].emplace_back(edge{mp[i][v[i][j]], v[i][j + 1] - v[i][j]}); vec[mp[i][v[i][j]]].emplace_back(edge{mp[i][v[i][j + 1]], v[i][j + 1] - v[i][j]}); } } dijkstra(); if(d[mp[n - 1][t]] == HINF()){ cout << -1 << endl; }else{ cout << d[1] << endl; } }