#include <bits/stdc++.h>
using namespace std;

// Template Headers {{{
using pii = pair<int, int>; using vpii = vector<pii>;
using vi = vector<int>; using vvi = vector<vi>;
using ll = long long; using vll = vector<long long>;
template <class T> using min_queue = priority_queue<T, vector<T>, greater<T>>;
template <class T> istream &operator>>(istream &, vector<T> &);
template <class T> ostream &operator<<(ostream &, const vector<T> &);
template <class T, class U> istream &operator>>(istream &, pair<T, U> &);
template <class T, class U> ostream &operator<<(ostream &, const pair<T, U> &);
template <class T> struct Inf { static constexpr T inf() { return std::numeric_limits<T>::has_infinity ? std::numeric_limits<T>::infinity() : std::numeric_limits<T>::max(); } };
template <> struct Inf<int> { static constexpr int inf() { return 0x3f3f3f3f; } };
template <> struct Inf<long long> { static constexpr long long inf() { return 0x3f3f3f3f3f3f3f3fLL; } };
constexpr int INF = Inf<int>::inf(); constexpr ll BINF = Inf<ll>::inf();
// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
// }}}

int solve() {
	int n, m, q; cin >> n >> m >> q;
	using jeng = pair<pii, pii>;
	vector<jeng> v(q); cin >> v;
	vi a(n);
	int ans = 0;
	function<void(int)> ha = [&] (int u) {
		if (u >= n) {
			int cur = 0;
			for (auto [ab, cd] : v) {
				auto [ai, bi] = ab;
				auto [ci, di] = cd;
				ai--, bi--;
				if (a[bi] - a[ai] == ci) {
					cur += di;
				}
			}
			ans = max(ans, cur);
		} else {
			int mn = 1;
			if (u > 0) mn = a[u - 1];
			for (int j = mn; j <= m; j++) {
				a[u] = j;
				ha(u + 1);
			}
		}
	};
	ha(0);
	cout << ans << endl;
	return 0;
}

// Template Main {{{
int main() {
	ios::sync_with_stdio(0); cin.tie(0);
	// precompute();
	// int t; cin >> t; for (int i=1;i<=t;i++)
	solve();
	// cout << "Case #" << i << ": ", solve();
	return 0;
}

template <class T> istream &operator>>(istream &is, vector<T> &v) {
	for (auto it=v.begin();it!=v.end();++it) is >> *it;
	return is;
}

template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
	for (auto it=v.begin();it!=v.end();) os << *it, os << " \n"[++it==v.end()];
	return os;
}

template <class T, class U> istream &operator>>(istream &is, pair<T, U> &p) {
	return is >> p.first >> p.second;
}

template <class T, class U> ostream &operator<<(ostream &os, const pair<T, U> &p) {
	return os << p.first << ' ' << p.second;
}
// }}}

// vim: fdm=marker
