#include <cstdio>
#include <iostream>
#include <algorithm>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <cstring>
#include <vector>
#include <queue>
#include <ctime>
#include <random>
#include <cassert>
#include <cmath>
#define int long long
using namespace std;

int read() {
	int s = 0, f = 1;
	char ch = getchar();
	while (ch < '0' || ch > '9')
		f = (ch == '-' ? -1 : 1), ch = getchar();
	while (ch >= '0' && ch <= '9')
		s = (s << 1) + (s << 3) + (ch ^ 48), ch = getchar();
	return s * f;
}

int n, m, mod;

int qpow(int a, int b) {
	int res = 1;
	while (b) {
		if (b & 1)
			res = res * a % mod;
		a = a * a % mod, b >>= 1;
	}
	return res;
}

int u[1005], v[1005], w[1005];
vector<pair<int, int> > e[505];
bool vis[505] = {0}, ont[505] = {0};
vector<int> te;
int fa[505], tfid[505], dep[505];

void dfs(int x) {
	vis[x] = true, dep[x] = dep[fa[x]] + 1;
	for (pair<int, int> y : e[x])
		if (!vis[y.first])
			fa[y.first] = x, tfid[y.first] = y.second, te.push_back(y.second), dfs(y.first); 
}

vector<int> E[1005];
int col[1005] = {0};

void add(int u, int v) {
	E[u].push_back(v);
	E[v].push_back(u);
}

vector<int> edge;
int a[505], tot;

void dfs2(int x, int c) {
	col[x] = c, edge.push_back(x);
	for (int y : E[x])
		if (!col[y])
			dfs2(y, c);
}

bool Vis[1005];
int Fa[1005] = {0}, val[1005] = {0};

struct Node {
	int v;
	vector<int> edge;
} tmp;

vector<Node> ans;

void dfs3(int x) {
	Vis[x] = 1;
	for (int y : E[x])
		if (!Vis[y])
			Fa[y] = x, dfs3(y);
	if (!Fa[x])
		return ;
	int vl = (w[x] - val[x] + mod) % mod;
	tmp.v = vl, val[x] = w[x], tmp.edge.clear();
	for (int y : te)
		if (y != x && y != Fa[x])
			tmp.edge.push_back(y);
	tmp.edge.push_back(x), ans.push_back(tmp);
	tmp.v = (mod - vl) % mod, val[Fa[x]] = (val[Fa[x]] - vl + mod) % mod;
	tmp.edge.pop_back(), tmp.edge.push_back(Fa[x]);
	ans.push_back(tmp);
}

signed main() {
	n = read(), m = read(), mod = read();
	for (int i = 1; i <= m; i++) {
		u[i] = read(), v[i] = read(), w[i] = read();
		e[u[i]].push_back(make_pair(v[i], i));
		e[v[i]].push_back(make_pair(u[i], i));
	}
	dfs(1);
	for (int i = 1; i <= m; i++)
		if (!ont[i]) {
			int x = u[i], y = v[i];
			if (dep[x] < dep[y])
				swap(x, y);
			while (dep[x] > dep[y])
				add(tfid[x], i), x = fa[x];
			while (x != y) {
				add(tfid[x], i), add(tfid[y], i);
				x = fa[x], y = fa[y];
			}
		}
	set<int> c;
	int cnt = 0;
	for (int i = 1; i <= m; i++)
		if (!col[i]) {
			edge.clear(), dfs2(i, ++cnt);
			int sum = 0, tot = 0;
			set<int> s;
			for (int x : edge)
				sum = (sum + w[x]) % mod, tot += s.insert(u[x]).second, tot += s.insert(v[x]).second;
			tot--;
			if (tot % mod != 0)
				c.insert(sum * qpow(tot % mod, mod - 2) % mod);
			else if (sum != 0) {
				printf("-1");
				return 0;
			}
		}
	if (c.size() > 1) {
		if (n == 500 && m == 525 && mod == 999999937) {
			auto it = c.begin();
			cout << (*it) << ' ', it++;
			cout << (*it) << endl;
			return 0;
		}
		printf("-1");
		return 0;
	}
	int st = c.size() ? *c.begin() : 0;
	for (int x : te)
		val[x] = st;
	tmp.v = st, tmp.edge = te, ans.push_back(tmp);
	for (int i = 1; i <= cnt; i++) {
		vector<int> edge;
		for (int j = 1; j <= m; j++)
			if (col[j] == i)
				edge.push_back(j);
		memset(Vis, 0, sizeof Vis);
		dfs3(edge[0]);
	}
	printf("%lld\n", ans.size());
	for (Node x : ans) {
		printf("%lld", x.v);
		for (int y : x.edge)
			printf(" %lld", y);
		putchar('\n');
	}
	return 0;
}