#include <bits/stdc++.h>

using namespace std;

using ll = long long;
const int MOD = 1E9 + 7;
const int INF = 1E9; const ll INFLL = 1E18;

const int MAX = 1E5;

bool ok = true;
bool span[MAX * 2];
bool seen[MAX];
ll w[MAX];
int depth[MAX];
vector<array<int, 3>> adj[MAX];
vector<array<int, 2>> segm;

struct FenwickTree {
	int n;
	vector<int> fen;
	FenwickTree(int n) {
		this->n = n;
		fen.resize(n);
	}
	int lso(int x) {
		return (x & (-x));
	}
	void update(int i, int x) {
		for(; i < n; i += lso(i)) {
			fen[i] += x;
		}
	}
	int query(int i) {
		int ans = 0;
		for(; i; i -= lso(i)) {
			ans += fen[i];
		}
		return ans;
	}
	int query(int i, int j) {
		return query(j) - query(i);
	}
};

int N; int M; 

void dfs(int x) {
	seen[x] = true;
	for(array<int, 3> i : adj[x]) {
		if(!seen[i[0]]) {
			w[i[0]] = w[x] + i[2];
			depth[i[0]] = depth[x] + 1;
			span[i[1]] = true;
			dfs(i[0]);
		}
	}
}

void dfs2(int x, int p) {
	for(array<int, 3> i : adj[x]) {
		if(i[0] == p) {
			continue;
		}
		if(span[i[1]]) {
			dfs2(i[0], x);
		} else {
			if(min(depth[x], depth[i[0]]) < depth[N - 1] && max(depth[x], depth[i[0]]) > depth[N - 1]) {
				ok = false;
			} else {
				if(w[x] - w[i[0]] != i[2]) {
					ok = false;
				}
				segm.push_back({depth[i[0]], depth[x]});
			}
		}
	}
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cin >> N >> M;
	for(int i = 0; i < M; i++) {
		int A; int B; int C;
		cin >> A >> B >> C;
		A--; B--;
		adj[A].push_back({B, i, C});
		adj[B].push_back({A, i, C});
	}
	dfs(0);
	dfs2(0, -1);
	if(ok) {
		stable_sort(segm.begin(), segm.end());
		FenwickTree fen(N + 1);
		for(array<int, 2> i : segm) {
			if(fen.query(i[0] + 1, i[1] + 1)) {
				ok = false;
			}
			fen.update(i[1] + 1, 1);
		}
	}
	cout << ok << "\n";
}