Buggy python submission (verdict: Runtime Error):
n,m,q = map(int,input().split())
a = [[int(i) for i in input().split()] for _ in range(q)]
b = []
for i in range(m):
    b.append(i+1)
import itertools
l = list(itertools.combinations_with_replacement(b,n))
max=0
from math import factorial
c = factorial(m) / factorial(n) / factorial(m - n)
#print(l)                                                                      

#for _ in range(int(c)):                                                       
for ll in l:
    m=0
#    print(ll)                                                                 
    for aa in a:
#        print(ll[aa[1]-1],ll[aa[0]-1],aa[2])                                  
        if ll[aa[1]-1]-ll[aa[0]-1]==aa[2]:
 #           print(aa[3])                                                      
            m+=aa[3]
    if max < m:
        max=m
  #  print(m,max)                                                              
print(max)


Fixed submission:
n,m,q = map(int,input().split())
a = [[int(i) for i in input().split()] for _ in range(q)]
b = []
for i in range(m):
    b.append(i+1)
import itertools
l = list(itertools.combinations_with_replacement(b,n))
max=0
#print(l)                                                                      
for ll in l:
    m=0
    for aa in a:
        if ll[aa[1]-1]-ll[aa[0]-1]==aa[2]:
            m+=aa[3]
    if max < m:
        max=m
print(max)

Buggy python submission (verdict: Runtime Error):
n,m,q = map(int,input().split())
a = [[int(i) for i in input().split()] for _ in range(q)]
b = []
for i in range(m):
    b.append(i+1)
import itertools
l = list(itertools.combinations_with_replacement(b,n))
max=0
from math import factorial
c = factorial(m) / factorial(n) / factorial(m - n)
#print(l)                                                                      

#for _ in range(int(c)):                                                       
for ll in l:
    m=0
#    print(ll)                                                                 
    for aa in a:
#        print(ll[aa[1]-1],ll[aa[0]-1],aa[2])                                  
        if ll[aa[1]-1]-ll[aa[0]-1]==aa[2]:
 #           print(aa[3])                                                      
            m+=aa[3]
    if max < m:
        max=m
  #  print(m,max)                                                              
print(max)


Fixed submission:
n,m,q = map(int,input().split())
a = [[int(i) for i in input().split()] for _ in range(q)]
b = []
for i in range(m):
    b.append(i+1)
import itertools
l = list(itertools.combinations_with_replacement(b,n))
max=0
#print(l)                                                                      
for ll in l:
    m=0
    for aa in a:
        if ll[aa[1]-1]-ll[aa[0]-1]==aa[2]:
            m+=aa[3]
    if max < m:
        max=m
print(max)

Buggy python submission (verdict: Runtime Error):
n,m,q = map(int,input().split())
a = [[int(i) for i in input().split()] for _ in range(q)]
b = []
for i in range(m):
    b.append(i+1)
import itertools
l = list(itertools.combinations_with_replacement(b,n))
max=0
from math import factorial
c = factorial(m) / factorial(n) / factorial(m - n)
#print(l)                                                                      

#for _ in range(int(c)):                                                       
for ll in l:
    m=0
#    print(ll)                                                                 
    for aa in a:
#        print(ll[aa[1]-1],ll[aa[0]-1],aa[2])                                  
        if ll[aa[1]-1]-ll[aa[0]-1]==aa[2]:
 #           print(aa[3])                                                      
            m+=aa[3]
    if max < m:
        max=m
  #  print(m,max)                                                              
print(max)


Fixed submission:
n,m,q = map(int,input().split())
a = [[int(i) for i in input().split()] for _ in range(q)]
b = []
for i in range(m):
    b.append(i+1)
import itertools
l = list(itertools.combinations_with_replacement(b,n))
max=0
#print(l)                                                                      
for ll in l:
    m=0
    for aa in a:
        if ll[aa[1]-1]-ll[aa[0]-1]==aa[2]:
            m+=aa[3]
    if max < m:
        max=m
print(max)

Buggy python submission (verdict: Runtime Error):
n,m,q = map(int,input().split())
a = [[int(i) for i in input().split()] for _ in range(q)]
b = []
for i in range(m):
    b.append(i+1)
import itertools
l = list(itertools.combinations_with_replacement(b,n))
max=0
from math import factorial
c = factorial(m) / factorial(n) / factorial(m - n)
#print(l)                                                                      

#for _ in range(int(c)):                                                       
for ll in l:
    m=0
#    print(ll)                                                                 
    for aa in a:
#        print(ll[aa[1]-1],ll[aa[0]-1],aa[2])                                  
        if ll[aa[1]-1]-ll[aa[0]-1]==aa[2]:
 #           print(aa[3])                                                      
            m+=aa[3]
    if max < m:
        max=m
  #  print(m,max)                                                              
print(max)

Fixed submission:
n,m,q = map(int,input().split())
a = [[int(i) for i in input().split()] for _ in range(q)]
b = []
for i in range(m):
    b.append(i+1)
import itertools
l = list(itertools.combinations_with_replacement(b,n))
max=0
#print(l)                                                                      
for ll in l:
    m=0
    for aa in a:
        if ll[aa[1]-1]-ll[aa[0]-1]==aa[2]:
            m+=aa[3]
    if max < m:
        max=m
print(max)