#include <cstdio>
#include <cstring>
#include <algorithm>
#include <numeric>
#include <vector>
#include <queue>
#include <map>
#include <cmath>
#include <cctype>
#include <set>

namespace uvu
{
#define LOCAL ____________DONT_DEFINE_ME____________
#define ll long long
#define inf 0x3f3f3f3f
// #define int long long
// #define inf 0x3f3f3f3f3f3f3f3fll
#define infll 0x3f3f3f3f3f3f3f3fll
#define debug(...) fprintf(stderr, __VA_ARGS__)
#define gline debug("now is #%d\n", __LINE__)
#define pii std::pair <int, int>
#define mkp std::make_pair
#define fi first
#define se second
char _ST_;
const int BUFSIZE = (1 << 20);
char ibuf[BUFSIZE], *iS = ibuf, *iT = ibuf;
char obuf[BUFSIZE], *oS = obuf, *oT = obuf + BUFSIZE;
char getc()
{
#ifdef LOCAL
	return getchar();
#else
	if(iS == iT) iT = (iS = ibuf) + fread(ibuf, 1, BUFSIZE, stdin);
	return iS == iT ? EOF : *iS++;
#endif
#define getchar ERR
}

void Flush() { fwrite(obuf, 1, oS - obuf, stdout); oS = obuf; }
struct Flusher { ~Flusher(){ Flush(); } }iamflusher;

void putc(char c)
{
#ifdef LOCAL
	putchar(c);
#else
	*oS++ = c;
	if(oS == oT) Flush();
#endif
#define putchar ERR
}

template <typename T = int> T read()
{
	T x = 0, f = 1; char c = getc();
	for(; !isdigit(c); c = getc()) if(c == '-') f = -1;
	for(;  isdigit(c); c = getc()) x = (x << 3) + (x << 1) + (c ^ 48);
	return x * f;
}

template <typename T> void print(T x, char c)
{
static int sta[BUFSIZE], top;
	top = 0;
	if(x < 0) putc('-'), x = -x;
	if(!x) sta[top = 1] = 0;
	for(; x; x /= 10) sta[++top] = x % 10;
	for(; top; ) putc(sta[top--] ^ 48);
	if(c) putc(c);
}

int readstr(char *s, int base)
{
	int idx = base - 1; char c = getc();
	for(; !(isdigit(c) || isalpha(c) || c == '#' || c == '.'); c = getc());
	for(;   isdigit(c) || isalpha(c) || c == '#' || c == '.' ; c = getc()) s[++idx] = c;
	return idx - base + 1;
}

void printf(const char *s) { for(; *s; s++) putc(*s); }
template <typename T, typename ... Args>
void printf(const char *s, T x, Args ... rest)
{
	for(; *s; s++)
	{
		if(*s != '%') { putc(*s); continue; }
		s++; if(*s == 'd') print(x, 0);
		else if(*s == 'c') putc(x);
		printf(s + 1, rest ...);
		return;
	}
}

template <typename T> void ckmax(T &x, T y) { x = x > y ? x : y; }
template <typename T> void ckmin(T &x, T y) { x = x < y ? x : y; }
 #define mod 998244353
// #define mod 1000000007
int sm(int x) { return x >= mod ? x - mod : x; }
void plus_(int &x, int y) { x = sm(x + y); }
void mul_(int &x, int y) { x = 1ll * x * y % mod; }
int ksm(int a, int b) { int res = 1; for(; b; b >>= 1, mul_(a, a)) if(b & 1) mul_(res, a); return res; }

#define N 500010
int n, m, K, S, fa[N], sz[N], tag[N];
int tot, sumtag, cntS;
int Find(int x) { return fa[x] == x ? x : Find(fa[x]); }
pii merge(int x, int y)
{
	x = Find(x), y = Find(y);
	if(x == y) return mkp(-1, -1);
	if(sz[x] > sz[y]) x ^= y ^= x ^= y;
	sumtag -= !!tag[x], sumtag -= !!tag[y];
	fa[x] = y, tag[y] += tag[x], sz[y] += sz[x];
	tot--; sumtag += !!tag[y];
	return mkp(x, y);
}
int x_[N], y_[N], z_[N];
int _x[N], _y[N], _z[N], p[N];
bool vis[N];
std::vector <pii> ivec[N << 2], dvec[N << 2];
std::map <pii, int> mp;
void ins(int k, int l, int r, int ql, int qr, pii z)
{
	if(ql > qr) return;
	if(ql <= l && r <= qr) { ivec[k].push_back(z); return; }
	int mid = (l + r) >> 1; 
	if(ql <= mid) ins(k << 1, l, mid, ql, qr, z);
	if(mid < qr)  ins(k << 1 | 1, mid + 1, r, ql, qr, z); 
}

void divide(int k, int l, int r)
{
	for(pii t : ivec[k])
	{
		if(t.se == S) std::swap(t.fi, t.se);
		int x = t.fi, y = t.se;
		if(x == S) 
		{  
			y = Find(y);
			cntS++;
			if(!tag[y]) 
			{
				sumtag++;
				tag[y] = 1;
				dvec[k].push_back(mkp(-1, y));
			}
		}
		else
		{
			pii t = merge(x, y);
			if(~t.fi) dvec[k].push_back(t);
		}
	}
	if(l == r)
	{
		if(!(sumtag == tot && tot <= K && cntS >= K))
		{
			vis[l] = 1;
			if(l) ins(1, 0, m, l + 1, m, mkp(x_[l], y_[l]));
		}
	}
	else
	{
		int mid = (l + r) >> 1;
		divide(k << 1, l, mid);
		divide(k << 1 | 1, mid + 1, r);
	}
	for(pii t : ivec[k]) if(t.fi == S || t.se == S) cntS--;
	std::reverse(dvec[k].begin(), dvec[k].end());
	for(pii t : dvec[k])
	{
		if(!~t.fi) sumtag--, tag[t.se] = 0;
		else 
		{
			sumtag -= !!tag[t.se];
			fa[t.fi] = t.fi, sz[t.se] -= sz[t.fi], tag[t.se] -= tag[t.fi], ++tot;
			sumtag += !!tag[t.fi]; sumtag += !!tag[t.se];
		}
	}
}

void solve()
{
	// memset(h, idx = -1, sizeof(h));
	n = read(), m = read(), K = read(), S = read();
	for(int i = 1; i <= n; i++) fa[i] = i, sz[i] = 1;
	tot = n - 1;
	for(int i = 1; i <= m; i++) 
	{
		_x[i] = read(), _y[i] = read(), _z[i] = read();
		if(mp[std::minmax(_x[i], _y[i])])
		{
			ckmin(_z[mp[std::minmax(_x[i], _y[i])]], _z[i]);
			i--, m--;
			continue;
		}
		mp[std::minmax(_x[i], _y[i])] = i;
	}
	std::iota(p + 1, p + 1 + m, 1);
	std::sort(p + 1, p + 1 + m, [&](int x, int y) -> bool { return _z[x] > _z[y]; });
	for(int i = 1; i <= m; i++) x_[i] = _x[p[i]], y_[i] = _y[p[i]], z_[i] = _z[p[i]];
	for(int i = 1; i <= m; i++) ins(1, 0, m, 0, i - 1, mkp(x_[i], y_[i]));
	divide(1, 0, m);
	if(vis[0]) { printf("nonnondayo\n"); return; }
	ll ans = 0;
	for(int i = 1; i <= m; i++) if(vis[i]) ans += z_[i];
	print(ans, '\n');
}

void init()
{
	
}

char _ED_;

void mian()
{
	debug("%.3f MB\n", abs(&_ST_ - &_ED_) / 1024.0 / 1024);
	init(); int T = 1;
	for(; T; solve(), T--);
}

#ifdef int
	#undef int
#endif
}

int main()
{
	// freopen("tmp.in", "r", stdin);
	// freopen("tmp.out", "w", stdout);
	uvu::mian(); return 0;
}