#include <limits>
#include <initializer_list>
#include <utility>
#include <bitset>
#include <tuple>
#include <type_traits>
#include <functional>
#include <string>
#include <array>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <iterator>
#include <algorithm>
#include <complex>
#include <random>
#include <numeric>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <regex>
#include <cassert>
#include <cstddef>
#include <variant>
#define endl codeforces
#define ALL(v) std::begin(v), std::end(v)
#define ALLR(v) std::rbegin(v), std::rend(v)
using ll = std::int64_t;
using ull = std::uint64_t;
using pii = std::pair<int, int>;
using tii = std::tuple<int, int, int>;
using pll = std::pair<ll, ll>;
using tll = std::tuple<ll, ll, ll>;
template <typename T> using vec = std::vector<T>;
template <typename T> using vvec = vec<vec<T>>;
template <typename T> const T& var_min(const T &t) { return t; }
template <typename T> const T& var_max(const T &t) { return t; }
template <typename T, typename... Tail> const T& var_min(const T &t, const Tail&... tail) { return std::min(t, var_min(tail...)); }
template <typename T, typename... Tail> const T& var_max(const T &t, const Tail&... tail) { return std::max(t, var_max(tail...)); }
template <typename T, typename... Tail> void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); }
template <typename T, typename... Tail> void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); }
template <typename T> T make_v(T init) { return init; }
template <typename T, typename... Tail> auto make_v(T init, std::size_t s, Tail... tail) { auto v = std::move(make_v(init, tail...)); return vec<decltype(v)>(s, v); }
template <typename T, std::size_t Head, std::size_t... Tail> struct multi_dem_array { using type = std::array<typename multi_dem_array<T, Tail...>::type, Head>; };
template <typename T, std::size_t Head> struct multi_dem_array<T, Head> { using type = std::array<T, Head>; };
template <typename T, std::size_t... Args> using mdarray = typename multi_dem_array<T, Args...>::type;
namespace init__ { struct InitIO { InitIO() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << std::fixed << std::setprecision(30); } } init_io; }

using query_type = std::tuple<ll, ll, ll, ll>;

ll calc_score(const vec<ll> &v, const vec<query_type> &qv) {
    ll ret = 0;
    for (auto [ a, b, c, d ] : qv) {
        ll diff = v[b] - v[a];
        if (diff == c) ret += d;
    }
    return ret;
}

ll dfs(ll idx, vec<ll> &v, ll pre, ll n, ll m, const vec<query_type> &qv) {
    if (idx == n) return calc_score(v, qv);
    ll ret = 0;
    for (ll i = pre; i <= m; i++) {
        v[idx] = i;
        chmax(ret, dfs(idx + 1, v, i, n, m, qv));
    }
    return ret;
}

int main() {
    ll n, m, q;
    std::cin >> n >> m >> q;
    vec<query_type> qv(q);
    for (auto &&e : qv) {
        ll a, b, c, d;
        std::cin >> a >> b >> c >> d;
        e = query_type(a - 1, b - 1, c, d);
    }
    vec<ll> buf(n);
    std::cout << dfs(0, buf, 1, n, m, qv) << "\n";
    return 0;
}


Measured memory_bytes: 3660