#include <bits/stdc++.h> using namespace std; // #include <ext/pb_ds/assoc_container.hpp> // #include <ext/pb_ds/tree_policy.hpp> // using namespace __gnu_pbds; typedef long long ll; typedef long double ld; typedef pair<int, int> pii ; typedef pair<ll, ll> pll ; typedef vector<pii> vii ; typedef vector<int> veci ; typedef vector<pll> vll ; typedef vector<ll> vecll; // find_by_order order_of_key //#pragma GCC optimize("O3,unroll-loops") //#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt") #define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> #define F first #define S second #define pb push_back #define endl '\n' #define Mp make_pair #define all(x) x.begin(), x.end() #define debug(x) cerr << #x << " = " << x << endl #define set_dec(x) cout << fixed << setprecision(x); #define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0); #define file_io freopen("in.txt" , "r" , stdin) ; freopen("out.txt" , "w" , stdout); #define lb lower_bound #define ub upper_bound #define for1(n) for(int i=1;i<=n;i++) #define for0(n) for(int i=0;i<n;i++) #define forn(n) for(int i=n;i>0;i--) #define pq priority_queue <pii, vector<pii>, greater<pii>> const ll mod = 1e9+7 ;// 998244353 ;// 1e9+9; ll inf=1e18; const int N=1e6+100,L=21,bs=701,NN=1e6; int n,m,k,q; vector<int>g[N],gg[N]; pii A[N]; bool check(int t,int x){ int tt=t; multiset<int>C,D; for1(n){ while(C.size() && (*C.begin())==i) C.erase(C.begin()); while(D.size() && (*D.begin())==i) D.erase(D.begin()); for(int x:g[i])C.insert(x); while(t+C.size()-D.size()>x){ auto it=C.end();it--; D.insert((*it)); C.erase(it); tt--; } } return (tt>=0); } int solve(int t){ int l=t-1,r=m; while(r-l!=1){ int mid=(l+r)>>1; if(check(t,mid)==0)l=mid; else r=mid; } return l+1; } int main(){ fast_io cin>>n>>m; for1(m){ cin>>A[i].F>>A[i].S;int t;cin>>t; if(A[i].F>A[i].S)swap(A[i].F,A[i].S); g[A[i].F].pb(A[i].S); } int ans=m; for0(m)if(solve(i))ans=min(ans,solve(i)); cout<<ans<<endl; }