#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#include<iostream>
#include<string>
#include<vector>
#include<utility>
#include<cmath>
#include<map>
#include<functional>
#include<queue>
#include<set>
#include<stack>
#include<iomanip>
#include<algorithm>
#include<unordered_map>
#include <numeric>
#include<string_view>
using namespace std;
using ll = long long;
#define rep(i,n) for(ll i=0;i<(n);i++)
#define all(i) i.begin(),i.end()
template<typename T =ll> using v = vector<T>;
template<typename T =ll> using vv = v<v<T>>;
template<typename T =ll,typename U =ll> using p = pair<T,U>;
template<typename T> T chmin(T &a,T b) {return a=min(a,b);}
template<typename T> T chmax(T &a,T b) {return a=max(a,b);}
const ll INF = (ll)1e18;
template <int MOD>
struct ModInt {
    using lint = long long;
    int val;

    // constructor
    ModInt(lint v = 0) : val(v % MOD) {
        if (val < 0) val += MOD;
    };

    // unary operator
    ModInt operator+() const { return ModInt(val); }
    ModInt operator-() const { return ModInt(MOD - val); }
    ModInt inv() const { return this->pow(MOD - 2); }

    // arithmetic
    ModInt operator+(const ModInt& x) const { return ModInt(*this) += x; }
    ModInt operator-(const ModInt& x) const { return ModInt(*this) -= x; }
    ModInt operator*(const ModInt& x) const { return ModInt(*this) *= x; }
    ModInt operator/(const ModInt& x) const { return ModInt(*this) /= x; }
    ModInt pow(lint n) const {
        auto x = ModInt(1);
        auto b = *this;
        while (n > 0) {
            if (n & 1) x *= b;
            n >>= 1;
            b *= b;
        }
        return x;
    }

    // compound assignment
    ModInt& operator+=(const ModInt& x) {
        if ((val += x.val) >= MOD) val -= MOD;
        return *this;
    }
    ModInt& operator-=(const ModInt& x) {
        if ((val -= x.val) < 0) val += MOD;
        return *this;
    }
    ModInt& operator*=(const ModInt& x) {
        val = lint(val) * x.val % MOD;
        return *this;
    }
    ModInt& operator/=(const ModInt& x) { return *this *= x.inv(); }

    // compare
    bool operator==(const ModInt& b) const { return val == b.val; }
    bool operator!=(const ModInt& b) const { return val != b.val; }

    // I/O
    friend std::istream& operator>>(std::istream& is, ModInt& x) noexcept { return is >> x.val; }
    friend std::ostream& operator<<(std::ostream& os, const ModInt& x) noexcept { return os << x.val; }
};

constexpr int MOD = 1e9 + 7;
using mint = ModInt<MOD>;

void a(){

}

void b(){

}

class c{
    
    ll n,m,q;
    using k = struct{ll r,s,t,u;};
    v<k> o;
    ll dfs(v<> A){
        if(A.size()==n){
            ll sum = 0;
            rep(i,q){
                if(A[o[i].s]-A[o[i].r]==o[i].t){
                    sum+=o[i].u;
                }
            }
            return sum;
        }
        ll ret = 0;
        A.push_back(A.back());
        while(A.back()<=m){
            chmax(ret,dfs(A));
            A.back()++;
        }
        
        return ret;
    }

    public:
    c(){
         cin >> n >> m >> q;
         o = v<k>(q,k{0,0,0,0});
         rep(i,q){
             cin >> o[i].r >> o[i].s >> o[i].t >> o[i].u;
             o[i].r--;
             o[i].s--;
         }
         ll ans = 0;
         rep(i,m+1){
             chmax(ans,dfs(v<>(1,i+1)));
         }
         cout << ans << endl;
    }
};


void d(){

}

void e(){

}

void f(){
    
}

int main(void){
    c();
    return 0;
 }


Measured memory_bytes: 3616