import sys
input = lambda : sys.stdin.readline().rstrip()
sys.setrecursionlimit(max(1000, 10**9))
write = lambda x: sys.stdout.write(x+"\n")

# グラフの読み込み
n,m = map(int, input().split())
import networkx as nx
g = nx.MultiDiGraph() # 必要に応じてMultiDiGraphにする
g.add_node(0, demand=-2)
for i in range(1,n-1):
    g.add_node(i)
g.add_node(n-1, demand=2)
for _ in range(m):
    u,v,c,d = map(int, input().split())
    u -= 1
    v -= 1
    g.add_edge(u,v,capacity=1, weight=c)
    g.add_edge(u,v,capacity=1, weight=d)
val, d = nx.network_simplex(g)
# d[u][v]: (u,v)の流量
ans = val
print(ans)