#include "fish.h"
#include<bits/stdc++.h>
#define pb push_back
#define pf push_front
//#define mp make_pair
#define F first
#define S second
#define ff first
#define ss second
#define str string
#define ll long long
#define ull unsigned ll
#define ld long double
#define pll pair<ll,ll>
#define plll pair<ll,pll>
#define pllll pair<pll,pll>
#define pld pair<ld,ld>
#define vl vector<ll>
#define vll vector<pll>
#define vlll vector<plll>
#define vllll vector<pllll>
#define vb vector<bool>
#define sz size()
#define fr front()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define bk back();
//#pragma GCC target( "sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")
using namespace std;
const ld pi=acos(-1.0);
const ll e5=1e5;
const ll e6=1e6;
const ll e9=1e9;
const ll inf=1e18;
const ll mod=1e9+7;
const ll mod2=998244353;
const ll MOD=106710087877475399;
const ll N=1e5+10;
ll bpm(ll x,ll y,ll m){if(y==0)return 1%m;if(y==1)return x%m;ll p=bpm(x,y/2,m);
if(y%2==0)return p*p%m;else return p*p%m*x%m;}
ll bp(ll x,ll y){if(y==0)return 1;if(y==1)return x;ll p=bp(x,y/2);
if(y%2==0)return p*p;else return p*p*x;}
ll s[N],dp[N];
long long max_weights(int N, int M, std::vector<int> X, std::vector<int> Y,std::vector<int> W){
    for(ll i=0;i<M;i++){
        s[X[i]]=W[i];
    }
    dp[0]=s[0];
    dp[1]=max(s[0],s[1]);
    for(ll i=2;i<N;i++){
        dp[i]=max(dp[i-1],dp[i-2]+s[i]);
    }
    return dp[N-1];
}