import std.stdio, std.conv, std.functional, std.string; import std.algorithm, std.array, std.container, std.range, std.typecons; import std.numeric, std.math, std.random; import core.bitop; string FMT_F = "%.10f"; static string[] s_rd; T RD(T = long)() { while(!s_rd.length) s_rd = readln.chomp.split; string res = s_rd[0]; s_rd.popFront; return res.to!T; } string RDR()() { return readln.chomp; } T[] ARR(T = long)(in string str, T fix = 0) { auto r = str.split.to!(T[]); r[] += fix; return r; } size_t[] MAKE_IDX(alias less = "a < b", Range)(Range range) { auto idx = new size_t[](range.length); makeIndex!(less)(range, idx); return idx;} size_t MIN_POS(alias less = "a < b", Range)(Range range) { auto r = minPos!(less)(range); return range.length - r.length; } bool inside(T)(T x, T b, T e) { return x >= b && x < e; } long lcm(long x, long y) { return x * y / gcd(x, y); } long mod = 10^^9 + 7; //long mod = 998244353; //long mod = 1_000_003; void moda(ref long x, long y) { x = (x + y) % mod; } void mods(ref long x, long y) { x = ((x + mod) - (y % mod)) % mod; } void modm(ref long x, long y) { x = (x * y) % mod; } void main() { auto N = RD; auto M = RD; auto P = RD-1; auto Q = RD-1; auto T = RD; auto edges = new long[2][][](N); foreach (i; 0..M) { auto a = RD-1; auto b = RD-1; auto c = RD; edges[a] ~= [b, c]; edges[b] ~= [a, c]; } long[] search(long pos) { long[2][] open = [[pos, 0]]; auto cost = new long[](N); cost.fill(long.max); cost[pos] = 0; while (!open.empty) { auto n = open.front; open.popFront; auto from = n[0]; auto c = n[1]; foreach (e; edges[from]) { auto to = e[0]; auto d = e[1]; if (c+d < cost[to]) { cost[to] = c+d; open ~= [to, c+d]; } } } return cost; } auto cost1 = search(0); auto cost2 = search(P); auto cost3 = search(Q); long ans = -1; foreach (i; 0..N) { auto cost_pq = max(cost2[i], cost3[i]); if ((cost1[i] + cost_pq)*2 <= T) { if ((cost1[i] + cost2[i] + cost3[i])*2 <= T) { ans = T; break; } else { long best = long.max; long pos; foreach (j; 0..N) { auto c2 = cost2[i] + cost2[j]; auto c3 = cost3[i] + cost3[j]; auto c = max(c2, c3); if (cost1[i] + c + cost1[j] > T) continue; if (c < best) { best = c; pos = j; } } if (best != long.max) { if (cost1[i] + best + cost1[pos] <= T) ans = max(ans, T - best); } } } } writeln(ans); stdout.flush(); debug readln(); }