#include <stdio.h>

int main(void) {
 int d[3];
 scanf("%d %d %d", &d[0],&d[1],&d[2]);

 int A[d[2]];
  int B[d[2]];
   int C[d[2]];
    int D[d[2]];
     int a[d[0]];
    int scorem=0;
   for (int j = 0; j < d[0]; j++)

            {
                a[j] = 1;

            }
         a[d[0]-1] = a[d[0] - 1]-1;
      for (int i = 0; i < d[2]; i++)
            {
                int tmp[4];
                scanf("%d %d %d %d",&tmp[0],&tmp[1],&tmp[2],&tmp[3]);
                A[i] = tmp[0];
                B[i] = tmp[1];
                C[i] = tmp[2];
                D[i] = tmp[3];
            }
        
      while (1)
            {
                if (a[0] == d[1]) break;
                int p_ = d[0]-1;
               for(int i = d[0]-1;i >=1;i--)
                {
                    if (a[i] - a[i - 1] >= 1) p_ = i-1;
                }
                //reset
                for (int i = 0; i <p_; i++)
                {
                    a[i] = 1;
                }
                a[p_]++;

                //得点
                int score = 0;
                for (int i = 0; i < d[2]; i++)
                {
                    int c = a[B[i] -1] - a[A[i] - 1]; //a_Bi - a_Ai
                    int c_ = C[i];//Ci
                    if (c == c_)
                    {
                        score += D[i];
                     //  RESULT(score);
                    }
                }
                if (scorem < score) scorem = score;

            }
            printf("%d",scorem);

  return 0;
}