#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T l, T r) { while (l != r) cerr << *l << " \n"[next(l)==r], ++l; }
#else
#define DE(...) 0
#define debug(...) 0
#endif
const int MAX_N = 300010;
const ll inf = 1ll << 55;
int n, m;
vector<pair<int,ll>> rc[MAX_N];
int32_t main() {
ios_base::sync_with_stdio(0), cin.tie(0);
cin >> n >> m;
vector<tuple<int,int,int>> req(m);
for (auto &[l, r, c] : req) {
cin >> l >> r >> c;
if (l > r) swap(l, r);
assert(c == 1);
}
vector<ll> sum(n + 10);
for (auto [l, r, c] : req)
sum[l] += c, sum[r] -= c;
for (auto [l, r, c] : req) rc[l].pb(r, c);
auto cal = [&](ll mx) {
// first is right end, second is count
priority_queue<pair<int,ll>> pq;
vector<ll> pfsum(sum);
ll use = 0;
for (int i = 1;i <= n;++i) {
for (auto [r, c] : rc[i])
pq.emplace(r, c);
pfsum[i] += pfsum[i-1];
while (pfsum[i] > mx) {
assert(pq.size());
auto [r, c] = pq.top(); pq.pop();
ll req = min(c, (pfsum[i] - mx + 1) / 2);
use += req;
pfsum[i] -= req * 2;
pfsum[r] += req * 2;
if (req < c) pq.emplace(r, c - req);
}
}
return mx + use;
};
ll res = inf;
for (int i = 0;i <= m;++i) {
chmin(res, cal(i));
}
cout << res << '\n';
}
