#include<bits/stdc++.h>
#define maxn 100005
typedef std::tuple<int,int,int> tu;
typedef std::pair<int,int> pr;
std::vector< std::pair<int,pr> > T[maxn];
std::pair<int,pr> mx[maxn];
std::pair<int,int> t1[maxn], t2[maxn];
bool check(pr A, pr B) {
	return A.first != B.first && A.first != B.second && A.second != B.first && A.second != B.second;
}
int getn(std::pair<int,int> p, int Y) {
	if (p.first == Y) {
		return p.second;
	}
	else if (p.second == Y) {
		return p.first;
	}
	else return 0;
}
int ans[maxn];
void solve(int P,int x,int y,int z,int val) {
	if (P == 1) {
		mx[x] = std::max(mx[x],{val,{y,z}});
	}
	if (P == 2) {
		if (check(mx[x].second,{y,z})) {
			ans[x] = std::max(ans[x], val + mx[x].first);
		}
	}
	if (P == 3) {
		int X = mx[x].second.first, Y = mx[x].second.second;
		int now = getn({y,z},Y);
		if (now == X || now == 0) {
			return ;
		}
		if (val > t1[x].first) t2[x] = t1[x], t1[x] = {val, now};
		else if (val > t2[x].first) t2[x] = {val, now};
	}
	if (P == 4){
		int X = mx[x].second.first, Y = mx[x].second.second;
		int now = getn({y,z},X);
		if (now == Y || now == 0) {
			return ;
		}
		int newval = (now == t1[x].second ? t2[x].first : t1[x].first);
		if (newval == 0) return;
		ans[x] = std::max(ans[x],val + newval);
	}
}

void get_triangles(int n,std::vector<tu>& eg) {
	std::vector< pr > e[maxn];
	int d[maxn],ed[maxn];
	memset(d,0,sizeof d);
	memset(ed,0,sizeof ed);
	for(auto v : eg) {
		d[std::get<1>(v)]++;
	}
	for(auto v : eg) {
		int x = std::get<0>(v), y = std::get<1>(v);
		if (std::make_pair(d[x], x) > std::make_pair(d[y], y)) {
			std::swap(x,y);
		}
		e[x].push_back({y,std::get<2>(v)});
	}
	for(int P = 1; P <= 4; P++) {
	for(int u = 1; u <= n; u++) {
		for(auto v : e[u]) {
			ed[v.first] = v.second;
		}
		for(auto v : e[u]) {
			for(auto w : e[v.first]) {
				if (ed[w.first] > 0) {
					int x = v.first, y = w.first, z = u, val = v.second + w.second + ed[w.first];
					solve(P,x,y,z,val);
					solve(P,y,x,z,val);
					solve(P,z,x,y,val);
				}
			}
		}
		for(auto v : e[u]) {
			ed[v.first] = 0;
		}
	}
	}
}
/*
int calc(std::vector< std::pair<int,pr> >&  vec) {
	std::pair<int,pr> mx = {0,{0,0}};
	for(auto i : vec) if (i > mx) {
		mx = i;
	}
	int ans = -1;
	for(auto i : vec) if (check(i.second,mx.second)) {
		ans = std::max(ans,i.first + mx.first);
	}
	std::pair<int,int> t1 = {0,0}, t2 = {0,0};
	int x = mx.second.first, y = mx.second.second;
	for(auto i : vec) {
		int now = getn(i.second,y);
		if (now == x || now == 0) {
			continue;
		}
		if (i.first > t1.first) t2 = t1, t1 = {i.first, now};
		else if (i.first > t2.first) t2 = {i.first, now};
	}
	for(auto i : vec) {
		int now = getn(i.second, x);
		if (now == y || now == 0) {
			continue;
		}
		int val = (now == t1.second ? t2.first : t1.first);
		if (val == 0) continue;
		ans = std::max(ans, i.first + val);
	}
	return ans;
}
*/
int main() {
	std::ios::sync_with_stdio(0);std::cin.tie(0);

	// freopen("in.txt","r",stdin);
	int n,m;
	std::cin >> n >> m;
	std::vector<tu> eg;
	for(int i=1;i<=m;i++) {
		int x,y,z;
		std::cin >> x >> y >> z;
		eg.push_back({x,y,z});
	}
	for(int i = 1;i <= n; i++) {
		ans[i] = -1;
	}
	get_triangles(n,eg);
	int Ans = -1;
	for(int i = 1;i <= n; i++) {
		Ans = std::max(Ans,ans[i]);
	}
	std::cout << Ans << std::endl;
}