#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define debug cerr << "-- " << __LINE__ << " --" << endl
#define MOD 1000000007
#define ALL(o) (o).begin(), (o).end()
typedef long long int ll;

using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
template <typename T> string to_string(const vector<T> &xs) {string s="["; for(int i=0;i<xs.size();i++) s += (i>0 ? " " : "") + to_string(xs[i]); return s + "]";}
template <typename T> ll argmax(const T &xs) {return distance(xs.begin(), max_element(xs.begin(), xs.end()));}
template <typename T> ll argmin(const T &xs) {return distance(xs.begin(), min_element(xs.begin(), xs.end()));}
ll nextLL(){ll x; scanf("%lld", &x); return x;}
int nextInt(){int x; scanf("%d", &x); return x;}
string nextString(){string s; cin >> s; return s;}


ll extgcd(ll a, ll b, ll &x, ll &y) {
    /* g を返す時点で ax + by == g となる */
    ll g = a; x = 1; y = 0;
    if (b != 0) g = extgcd(b, a % b, y, x), y -= (a / b) * x;
    return g;
}
ll gcd(ll a, ll b) { ll x, y; return extgcd(a, b, x, y); }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

ll remainder(ll x, ll y) {assert(y > 0); ll r = x % y; if (r < 0) r += y; return r;}
ll quotient(ll x, ll y) {assert(y > 0); return (x - remainder(x, y)) / y;}

class llm{
	ll n;
public:
	llm(){n = 0;}
	llm(ll n){this->n = (n >= 0) ? (n % MOD) : (MOD - 1 - (-n-1 % MOD));}
	operator ll() const {return n;}
	llm operator+(const llm &y) const{ return llm((ll)*this + (ll)y);}
	llm operator+=(const llm &y) { *this = *this + y; return *this;}
	llm operator-(const llm &y) const{ return llm((ll)*this - (ll)y);}
	llm operator-=(const llm &y) { *this = *this - y; return *this;}
	llm operator-() const{ return llm(0) - *this;}
	llm operator*(const llm &y) const{ return llm((ll)*this * (ll)y);}
	llm operator*=(const llm &y) { *this = *this * y; return *this;}
	llm operator/(const llm &y) const{ return *this * y.inv();}
	llm operator/=(const llm &y) { *this = *this / y; return *this;}
	llm inv() const{
		ll x, y;
		if (extgcd(n, MOD, x, y) == 1) return llm(x);
  		return llm(0); // unsolvable
	}
	friend istream& operator >> (istream& os, llm& x);
	friend ostream& operator << (ostream& os, const llm& x);
};
istream& operator >> (istream& is, llm& x){ll n; is >> n; x = llm(n); return is;}
ostream& operator << (ostream& os, const llm& x){os << (ll)x; return os;}

template<typename T> T comb(ll n, ll k){
	T ret = 1;
	for(ll i=1;i<=k;i++) ret = ret * T(n - k + i) / T(i);
	return ret;
}

vector<ll> x(10);
ll n, m, q;
ll a[50], b[50], c[50], d[50];


int main(void){
	cin >> n >> m >> q;
	for(ll i=0;i<q;i++){
		cin >> a[i] >> b[i] >> c[i] >> d[i];
		a[i]--; b[i]--;
	}

	for(ll i=0;i<n;i++) x[i] = 1;
	ll maxi = 0;
	for(ll i=0;;i++){
		ll sc = 0;
		for(ll j=0;j<q;j++){
			if (x[b[j]] - x[a[j]] == c[j]) sc += d[j];
		}
		maxi = max(sc, maxi);

		bool end = true;
		for(ll j=0;j<n;j++){
			if (x[n-1-j] < m){
				ll cnt = 0, offs = x[n-1-j]+1;
				for(ll k=n-1-j;k<n;k++,cnt++){
					x[k] = offs;
				}
				end = false;
				break;
			}
		}
		// cerr << to_string(x) << endl;
		if (end) break;
	}
	cout << maxi << endl;

	

    return 0;
}




Measured memory_bytes: 3624