#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define int long long #define ii pair #define app push_back #define all(a) a.begin(), a.end() #define bp __builtin_popcountll #define ll long long #define mp make_pair #define x first #define y second #define Time (double)clock()/CLOCKS_PER_SEC #define debug(x) std::cerr << #x << ": " << x << '\n'; #define FORI(i,a,b) for (int i = (a); i < (b); ++i) #define FOR(i,a) FORI(i,0,a) #define ROFI(i,a,b) for (int i = (b)-1; i >= (a); --i) #define ROF(i,a) ROFI(i,0,a) #define rep(a) FOR(_,a) #define each(a,x) for (auto& a: x) #define FORN(i, n) FORI(i, 1, n + 1) using vi = vector; template std::istream& operator >>(std::istream& input, std::pair & data) { input >> data.x >> data.y; return input; } template std::istream& operator >>(std::istream& input, std::vector& data) { for (T& x : data) input >> x; return input; } template std::ostream& operator <<(std::ostream& output, const pair & data) { output << "(" << data.x << "," << data.y << ")"; return output; } template std::ostream& operator <<(std::ostream& output, const std::vector& data) { for (const T& x : data) output << x << " "; return output; } std::ostream& operator <<(std::ostream& output, const __int128 &x) { __int128 n = x; if (n == 0) { output << "0"; return output; } if (n < 0) { n = -n; output << "-"; } string s; while (n) { s += '0' + (n%10); n /= 10; } reverse(all(s)); cout << s; return output; } ll div_up(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up ll div_down(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down ll math_mod(ll a, ll b) { return a - b * div_down(a, b); } #define tcT template using V = vector; tcT> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; } // set a = min(a,b) tcT> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; } ll gcd(ll a, ll b) { while (b) { tie(a, b) = mp(b, a % b); } return a; } int Bit(int mask, int bit) { return (mask >> bit) & 1; } const int N = 2e5+7; V g[N]; int dist[N]; signed main() { #ifdef LOCAL #else #define endl '\n' ios_base::sync_with_stdio(0); cin.tie(0); #endif int n, m, k; cin >> n >> m >> k; V ed; rep (m) { int u, v, c; cin >>u >>v>>c; ed.app({u, v, c}); } auto check = [&] (int key) { FOR (i, N) { g[i].clear(); dist[i] = N; } //k-th min <= key each (e, ed) { int u = e[0], v = e[1]; if (e[2] <= key) { g[u].app(mp(v, 0)); g[v].app(mp(u, 0)); } else { g[u].app(mp(v, 1)); g[v].app(mp(u, 1)); } } deque q; dist[1] = 0; q.push_back(1); while (q.size()) { int u = q.front(); q.pop_front(); each (e, g[u]) { int v = e.x, c = e.y; if (ckmin(dist[v], dist[u] + c)) { if (c == 0) { q.push_front(v); } else { q.push_back(v); } } } } return dist[n] < k; }; int l = -1, r = N; while (l < r - 1) { int m = (l + r) / 2; if (check(m)) { r = m; } else { l = m; } } cout << r << endl; }