/*
                    !!!!!!                                                     
                    !!!!!!!!!!                                                 
                     !!!!!!!!!!!!!!!                                           
                       !!!!!!!!!!!!!!                                          
                     !!!!!!!!!!!!!!!                                           
                      !!!!!!!!!!!!                                             
                      !!!!!!!!!!!!                                             
                        !!!!!!!!!!!!                                           
                        !!!!!!!!                                               
                        !!!!!!!!!!                                             
                       !!!!!!!!!!!!!!                                          
                     !!!!!!!!!!!!!!!!                                          
                    !!!!!!!!!!!!!!!!                                  !!!!!    
                  !!!!!!!!!!!!!!!!!!!                               !!!!!!!!!! 
                 !!!!!!!!!!!!!!!!!!!!!!!                 !         !!!!!!!!!!  
            !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!              !!     !!!!!!!!!!!!    
           !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!        !!      !!!!!!!!       
            !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!      
             !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!       
              !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  !!!!!!!!!!!!       
       !!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!        !!!!!!        
      !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!      !!!!!         
          !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!        !!!          
        !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!        !          
          !!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                       
           !!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                         
                  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                          
                 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                           
                  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                               
                  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                               
                  !!!!!!!!!!!!!!!!!!!!!!!!!!!!                                 
                  !!!!!!!!!!!!!!!!!!!!!!!!!!                                   
                  !!!!!!!!!!!!!!!!!!!!!!!!!                                    
                   !!!!!!!!!!!!!!!!!!!!!!!!                                    
                    !!!!!!!!!!!!!!!!!!!!                                       
                    !!!!!!!!!!!!!!!!!!!                                        
                     !!!!!!!!!!!!!!!!                                          
                      !!!!!!!!!!!!!!!!                                         
                      !!!!!!!!!!!!!!!                                          
                       !!!!!!!!!!!!!!                                          
                        !!!!!!!!!!!!                                           
                        !!!!!!!!!!!!                                           
                        !!!!!!!!!!!!                                           
                          !!!!!!!!                                             
                          !!!!!!                                               
                           !!!! 
*/                                               
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/trie_policy.hpp>

#define MAXN 200005
#define mod 1000000007 
#define inf LLONG_MAX/3
#define pb push_back
using namespace std;
/*
 *  author  :  vivekcrux
 */
typedef long long ll; 
typedef pair<ll,ll> pll;


ll power(ll x,ll y,ll m=mod)
{
  ll ans = 1;
  while(y>0)
  {
    if(y&1)
    {
      ans = (ans*x)%m;
    }
    x = (x*x)%m;  
    y /= 2;
  }
  return ans%m;
}

ll modInverse(ll a, ll m=mod) 
{ 
    ll m0 = m; 
    ll y = 0, x = 1; 
  
    if (m == 1) 
      return 0; 
  
    while (a > 1) 
    { 
        // q is quotient 
        ll q = a / m; 
        ll t = m; 
  
        // m is remainder now, process same as 
        // Euclid's algo 
        m = a % m, a = t; 
        t = y; 
  
        // Update y and x 
        y = x - q * y; 
        x = t; 
    } 
  
    // Make x positive 
    if (x < 0) 
       x += m0; 
  
    return x; 
} 

ll n,m,q,a[51],b[51],c[51],d[51];
ll arr[10],res;

void solve(ll ind,ll prev)
{
  if(ind == n)
  {
    /*for(ll i=0;i<n;i++)
      cout<<arr[i]<<" ";
    cout<<"\n";*/
    ll ret = 0;
    for(ll i=0;i<q;i++)
    {
      if(arr[b[i]]-arr[a[i]] == c[i])
        ret += d[i];
    }
    res = max(res,ret);
    return;
  }
  for(ll i=prev;i<=m;i++)
  {
    arr[ind] = i;
    solve(ind+1,i);
  }
}


int main()
{
  /*#ifndef ONLINE_JUDGE 
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout); 
  #endif*/

  ios_base::sync_with_stdio(false);
  cin.tie(NULL);

  ll T=1;
  // cin>>T;  
  while(T--)
  {
    ll k,i,j,ans=0;
    cin>>n>>m>>q;
    for(i=0;i<q;i++)
    {
      cin>>a[i]>>b[i]>>c[i]>>d[i];
      a[i]--;
      b[i]--;
    }
    res = 0;
    solve(0,1);
    cout<<res;
  }
  return 0;
} 

Measured memory_bytes: 3652