n, m, q = map(int, input().split())
x = []
for i in range(q):
    a, b, c, d = map(int, input().split())
    x.append([a, b, c, d])
ans = 0

if n == 2:
    for i1 in range(1, m + 1):
        for i2 in range(i1, m + 1):
            l = [i1, i2]
            v = 0
            for j in x:
                if l[j[1] - 1] - l[j[0] - 1] == j[2]:
                    v += j[3]
            ans = max(ans, v)
elif n == 3:
    for i1 in range(1, m + 1):
        for i2 in range(i1, m + 1):
            for i3 in range(i2, m + 1):
                l = [i1, i2, i3]
                v = 0
                for j in x:
                    if l[j[1] - 1] - l[j[0] - 1] == j[2]:
                        v += j[3]
                ans = max(ans, v)
elif n == 4:
    for i1 in range(1, m + 1):
        for i2 in range(i1, m + 1):
            for i3 in range(i2, m + 1):
                for i4 in range(i3, m + 1):
                    l = [i1, i2, i3, i4]
                    v = 0
                    for j in x:
                        if l[j[1] - 1] - l[j[0] - 1] == j[2]:
                            v += j[3]
                    ans = max(ans, v)
elif n == 5:
    for i1 in range(1, m + 1):
        for i2 in range(i1, m + 1):
            for i3 in range(i2, m + 1):
                for i4 in range(i3, m + 1):
                    for i5 in range(i4, m + 1):
                        l = [i1, i2, i3, i4, i5]
                        v = 0
                        for j in x:
                            if l[j[1] - 1] - l[j[0] - 1] == j[2]:
                                v += j[3]
                        ans = max(ans, v)
elif n == 6:
    for i1 in range(1, m + 1):
        for i2 in range(i1, m + 1):
            for i3 in range(i2, m + 1):
                for i4 in range(i3, m + 1):
                    for i5 in range(i4, m + 1):
                        for i6 in range(i5, m + 1):
                            l = [i1, i2, i3, i4, i5, i6]
                            v = 0
                            for j in x:
                                if l[j[1] - 1] - l[j[0] - 1] == j[2]:
                                    v += j[3]
                            ans = max(ans, v)
elif n == 7:
    for i1 in range(1, m + 1):
        for i2 in range(i1, m + 1):
            for i3 in range(i2, m + 1):
                for i4 in range(i3, m + 1):
                    for i5 in range(i4, m + 1):
                        for i6 in range(i5, m + 1):
                            for i7 in range(i6, m + 1):
                                l = [i1, i2, i3, i4, i5, i6, i7]
                                v = 0
                                for j in x:
                                    if l[j[1] - 1] - l[j[0] - 1] == j[2]:
                                        v += j[3]
                                ans = max(ans, v)
elif n == 8:
    for i1 in range(1, m + 1):
        for i2 in range(i1, m + 1):
            for i3 in range(i2, m + 1):
                for i4 in range(i3, m + 1):
                    for i5 in range(i4, m + 1):
                        for i6 in range(i5, m + 1):
                            for i7 in range(i6, m + 1):
                                for i8 in range(i7, m + 1):
                                    l = [i1, i2, i3, i4, i5, i6, i7, i8]
                                    v = 0
                                    for j in x:
                                        if l[j[1] - 1] - l[j[0] - 1] == j[2]:
                                            v += j[3]
                                    ans = max(ans, v)
elif n == 9:
    for i1 in range(1, m + 1):
        for i2 in range(i1, m + 1):
            for i3 in range(i2, m + 1):
                for i4 in range(i3, m + 1):
                    for i5 in range(i4, m + 1):
                        for i6 in range(i5, m + 1):
                            for i7 in range(i6, m + 1):
                                for i8 in range(i7, m + 1):
                                    for i9 in range(i8, m + 1):
                                        l = [i1, i2, i3, i4, i5, i6, i7, i8, i9]
                                        v = 0
                                        for j in x:
                                            if l[j[1] - 1] - l[j[0] - 1] == j[2]:
                                                v += j[3]
                                        ans = max(ans, v)
else:
    for i1 in range(1, m + 1):
        for i2 in range(i1, m + 1):
            for i3 in range(i2, m + 1):
                for i4 in range(i3, m + 1):
                    for i5 in range(i4, m + 1):
                        for i6 in range(i5, m + 1):
                            for i7 in range(i6, m + 1):
                                for i8 in range(i7, m + 1):
                                    for i9 in range(i8, m + 1):
                                        for i10 in range(i9, m + 1):
                                            l = [i1, i2, i3, i4, i5, i6, i7, i8, i9, i10]
                                            v = 0
                                            for j in x:
                                                if l[j[1] - 1] - l[j[0] - 1] == j[2]:
                                                    v += j[3]
                                            ans = max(ans, v)

print(ans)


Measured memory_bytes: 9408