#include "bits/stdc++.h"
using namespace std;

#define DEBUG(x) cout<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cout<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl


typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define rep1(i,n) for(ll i=1;i<=(ll)(n);i++)
#define rrep(i,n) for(ll i=(ll)(n)-1;i>=0;i--)
#define rrep1(i,n) for(ll i=(ll)(n);i>0;i--)
#define REP(i,a,b) for(ll i=(ll)a;i<(ll)b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(v) v.begin(),v.end()
#define UNIQUE(v) v.erase(unique(all(v)), v.end())
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
const ll inf = 1000000001;
const ll INF = 2e18;
//const ll MOD = 1000000007;
const double pi = 3.14159265358979323846;
#define Sp(p) cout<<setprecision(15)<< fixed<<p<<endl;
int dx[4] = { 1,0, -1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
#define mp make_pair

const int N = 100010;
int n, m;
vector<vector<pll> > G(N);
vector<pair<ll, bool> > d(N, mp(INF, 0));
ll a = INF;
ll mi, ma;

bool dfs(bool sei, ll x, int u) {
	//DEBUG(u); DEBUG(sei); DEBUG(x);
	rep(i, G[u].size()) {
		int v = G[u][i].first;
		ll s = G[u][i].second;
		if (d[v].first == INF) {
			if (sei) {
				d[v] = pll(s - x, false);
				ma = min(ma, s - x - 1);
				if (!dfs(false, s - x, v)) {
					return false;
				}
			}
			else {
				d[v] = pll(s - x, true);
				mi = max(mi, 1 - s + x);
				if (!dfs(true, s - x, v)) {
					return false;
				}
			}
		}
		else {
			ll nx = s - x;
			bool nf = !sei;
			if (sei) {
				if (!d[v].second) {
					if (s - x != d[v].first) {
						return false;
					}
				}
				else {
					ll f = d[v].first;
					if ((s - x - f) % 2 == 1) {
						return false;
					}
					else {
						ll ans = (s - x - f) / 2;
						if (!in(ans, mi, ma + 1)) {
							return false;
						}
						else {
							mi = ans; ma = ans;
						}
					}
				}
			}
			else {
				if (d[v].second) {
					if (s - x != d[v].first) {
						return false;
					}
				}
				else {
					ll f = d[v].first;
					if ((f - s + x) % 2 == 1) {
						return false;
					}
					else {
						ll ans = (f - s + x) / 2;
						if (!in(ans, mi, ma + 1)) {
							return false;
						}
						else {
							mi = ans; ma = ans;
						}
					}
				}
			}
		}

	}
}

int main() {
	cin >> n >> m;
	rep(i, m) {
		int u, v, s;
		cin >> u >> v >> s;
		u--; v--;
		G[u].push_back(pll(v, s));
		G[v].push_back(pll(u, s));
	}
	ll ans = 1;
	rep(i, n) {
		if (d[i].first != INF) {
			continue;
		}
		mi = -1; ma = INF;
		a = INF;
		if (!dfs(true, 0, i)) {
			ans *= 0;
		}
		else {
			if (ma < mi) {
				ans *= 0;
			}
			else {
				ans *= (ma - mi + 1);
			}
		}
	}
	cout << ans << endl;


}

Measured memory_bytes: 14080