def solve():
    N, M = map(int, raw_input().split())

    mat = [[0] * N for i in range(N)]

    for i in range(M):
        i1, i2, sc = map(int, raw_input().split())
        mat[i1][i2] += sc

    lis = list(range(N))

    lis.sort(cmp=lambda l, r: mat[r][l] - mat[l][r])

    ans = 0
    for i in range(N):
        for j in range(i + 1, N):
            a = lis[i]
            b = lis[j]
            ans += mat[a][b]

    print(ans)


if __name__ == '__main__':
    solve()