n, m = map(int, input().split())

item1 = []
item2 = []
score = []

for _ in range(m):
    i1, i2, s = map(int, input().split())
    item1.append(i1)
    item2.append(i2)
    score.append(s)
    
score1 = 0
score2 = 0

for i in range(m):
    if item1[i] < item2[i]:
        score1 += score[i]
        
for i in range(m):
    if item1[i] > item2[i]:
        score2 += score[i]
        
if score1 > score2:
    print(score1)
else:
    print(score2)