#include <bits/stdc++.h>
#define PII pair<int, int>
#define INF 2e9
#define ll long long
using namespace std;
const int N = 5e4 + 3;
const int M = 5e5 + 3;

inline int read() {
	char ch = getchar(); int x = 0, f = 1;
	while (!isdigit(ch)) {if (ch == '-') {f = -1;} ch = getchar();}
	while (isdigit(ch)) {x = x * 10 + ch - 48; ch = getchar();}
	return x * f;
}

struct node {
	int x, y, z;
}e[M];
int n, m, k, s, val[N], ex[N], fa[N], tot;
ll ans;
vector<PII> vec, Vec;

inline int getfa(int x) {return x == fa[x] ? x : fa[x] = getfa(fa[x]);}

int main() {
	scanf("%d%d%d%d", &n, &m, &k, &s);
	for (int i = 1; i <= n; ++i) fa[i] = i, val[i] = INF;
	for (int i = 1, x, y, z; i <= m; ++i) {
		x = read(); y = read(); z = read();
		if (x == s) val[y] = min(val[y], z);
		else if (y == s) val[x] = min(val[x], z);
		else tot++, e[tot].x = x, e[tot].y = y, e[tot].z = z;
	}
	sort(e + 1, e + 1 + tot, [&](node p, node q) {return p.z < q.z;});
	for (int i = 1, x, y, z; i <= tot; ++i) {
		x = e[i].x; y = e[i].y; z = e[i].z;
		x = getfa(x); y = getfa(y);
		if (x == y) continue;
		ans += z;
		if (val[x] > val[y]) swap(x, y);
		fa[y] = x; ex[y] = z;
	}
	int mem = 0;
	for (int i = 1; i <= n; ++i) {
		if (i == s) continue;
		if (getfa(i) ^ i) continue;
		if (val[i] == INF) return puts("nonnondayo"), 0;
		mem++; ans += val[i];
	}
	if (mem > k) return puts("nonnondayo"), 0;
	for (int i = 1; i <= n; ++i) {
		if (i == s) continue;
		if (getfa(i) == i) continue;
		if (val[i] == INF) continue;
		if (val[i] < ex[i]) vec.push_back(make_pair(ex[i], val[i] - ex[i]));
		else Vec.push_back(make_pair(val[i], val[i] - ex[i]));
	}
	sort(vec.begin(), vec.end()); reverse(vec.begin(), vec.end());
	sort(Vec.begin(), Vec.end()); for (auto tmp : Vec) vec.push_back(tmp);
	if (vec.size() + mem < k) return puts("nonnondayo"), 0;
	sort(vec.begin(), vec.end());
	for (int i = 0; i < k - mem; ++i) ans += vec[i].second;
	return printf("%lld\n", ans), 0;
}