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 ll  long long int
#define ull unsigned long long 
#define ff first
#define ss second
#define fast ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define pb push_back 
#define mp make_pair
#define inf 2000000009
#define mod 1000000007
#define ld long double
using namespace std;
ll ans;
vector<ll> a,b,c,d;
vector<ll>temp;
ll n,m,q;

ll fun()
{
    ll ans=0;
    for(ll i=0;i<q;i++)
        if(temp[b[i]]-temp[a[i]]==c[i])
            ans+=d[i];
        return ans;
}

void dfs(ll lim)
{
    if(temp.size()==n+1)
    ans=max(ans,fun());
    else
    {
        for(ll i=lim;i<=m;i++)
           {
            temp.pb(i);
            dfs(i);
            temp.pop_back();
           }
    }
}


int main()
{ 
fast;

cin>>n>>m>>q;

a.assign(q,0);
b.assign(q,0),c.assign(q,0),d.assign(q,0);
for(ll i=0;i<q;i++)cin>>a[i]>>b[i]>>c[i]>>d[i];
    ans=0;

for(ll i=1;i<=m;i++)
    temp.clear(),temp.pb(i),dfs(i);

cout<<ans;

}