Problem:
Score : 300 points

Problem Statement

Given are positive integers N, M, Q, and Q quadruples of integers ( a_i , b_i , c_i , d_i ).

Consider a sequence A satisfying the following conditions:

A is a sequence of N positive integers.

1 \leq A_1 \leq A_2 \le \cdots \leq A_N \leq M.

Let us define a score of this sequence as follows:

The score is the sum of d_i over all indices i such that A_{b_i} - A_{a_i} = c_i. (If there is no such i, the score is 0.)

Find the maximum possible score of A.

Constraints

All values in input are integers.

2 ≤ N ≤ 10

1 \leq M \leq 10

1 \leq Q \leq 50

1 \leq a_i < b_i \leq N ( i = 1, 2, ..., Q )

0 \leq c_i \leq M - 1 ( i = 1, 2, ..., Q )

(a_i, b_i, c_i) \neq (a_j, b_j, c_j) (where i \neq j)

1 \leq d_i \leq 10^5 ( i = 1, 2, ..., Q )

Input

Input is given from Standard Input in the following format:

N M Q
a_1 b_1 c_1 d_1
:
a_Q b_Q c_Q d_Q

Output

Print the maximum possible score of A.

Sample Input 1

3 4 3
1 3 3 100
1 2 2 10
2 3 2 10

Sample Output 1

110

When A = \{1, 3, 4\}, its score is 110. Under these conditions, no sequence has a score greater than 110, so the answer is 110.

Sample Input 2

4 6 10
2 4 1 86568
1 4 0 90629
2 3 0 90310
3 4 1 29211
3 4 3 78537
3 4 2 8580
1 2 1 96263
1 4 2 2156
1 2 0 94325
1 4 3 94328

Sample Output 2

357500

Sample Input 3

10 10 1
1 10 9 1

Sample Output 3

1

Solution in C++ (GCC 9.2.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
#define REP(i,s,e) for(int i=(s); i<(e);i++)
#define rep(i,n) REP(i,0,n)
#define rep1(i,n) REP(i,1,n)
#define repe(i,n) for(auto &&i:n)
#define all(v) (v).begin(),(v).end()
#define decimal fixed<<setprecision(20)
#define fastcin() cin.tie(0);ios::sync_with_stdio(false)
//#define int long long
using LL = long long;
using namespace std;
using Graph = vector<vector<int>>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = 1e9;
const LL LLINF = 1e16;
const int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0};

int v[11];
int n, m, q;
vector<vector<int>> g;

LL ans = 0;
void dfs(int d){
    if(d == n){
        LL tmp = 0;
        repe(now, g){
            if(v[now[1]]-v[now[0]]==now[2]) tmp += now[3];
        }
        chmax(ans, tmp);
    }else if(d == 0){
        rep1(i, m+1){
            v[d] = i;
            dfs(d+1);
        }
    }else{
        REP(i, v[d-1], m+1){
            v[d] = i;
            dfs(d+1);
        }
    }
}

signed main(){
    fastcin();
    cin >> n >> m >> q;
    rep(i, q){
        int a,b,c,d;
        cin >> a >> b >> c >> d;
        a--;b--;
        g.push_back({a,b,c,d});
    }
    dfs(0);
    cout << ans << endl;
}