#include <bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define ll long long int
#define tc ll test;cin >> test;while(test--)
#define vi vector<ll>
#define pll pair<ll,ll>
#define pb push_back
#define mp make_pair
#define INF 1e18
#define MOD 1000000007
#define ff first
#define ss second
#define in >>
#define out <<
#define space << " " <<
#define spacef << " "
#define fo(i,a,b) for(ll i = a; i <= b; i++)
#define nextline out "\n"
#define print(x) for(auto i : x ) cout out i spacef
#define mmax(x,i) x = max(x,i)
#define mmin(x,i) x = min(x,i)
#define N 105
int main() {
fast;
ll n,m;
cin in n in m;
vi first;
vi second;
fo(i,1,m){
ll a,b,c;
cin in a in b in c;
if(a == 1) first.pb(c);
else second.pb(c);
}
sort(first.begin(),first.end());
sort(second.rbegin(),second.rend());
ll minans = INF;
fo(i,0,m/2 - 1) mmin(minans,first[i]+second[i]);
cout out minans;
return 0;
}
