from networkx import*
N, M = map(int, input().split())
G = MultiDiGraph()
G.add_nodes_from([i for i in range(1, N - 1)])
G.add_node(0, demand = -2)
G.add_node(N - 1, demand = 2)
for i in range(M):
    x, y, c, d = map(int, input().split())
    x, y = x-1, y-1
    G.add_weighted_edges_from([(x, y, c), (x, y, d)], capacity = 1)

print(min_cost_flow_cost(G))