mod = 1000000007 eps = 10**-9 def main(): import sys input = sys.stdin.buffer.readline from heapq import heappush, heappop class Mincostflow(): def __init__(self, N): self.N = N self.adj = [[] for _ in range(N + 1)] self.inf = 1 << 60 def add_edge(self, fr, to, cap, cost): # [to, cap, cost, rev] forward = [to, cap, cost, None] backward = forward[3] = [fr, 0, -cost, forward] self.adj[fr].append(forward) self.adj[to].append(backward) def flow(self, s, t, f): N = self.N adj = self.adj inf = self.inf res = 0 H = [0] * (N + 1) prev_v = [0] * (N + 1) prev_e = [None] * (N + 1) dist0 = [inf] * (N + 1) dist = [inf] * (N + 1) while f: dist[:] = dist0 dist[s] = 0 pq = [(0, s)] while pq: d, v = heappop(pq) if d > dist[v]: continue r0 = dist[v] + H[v] for e in adj[v]: u, cap, cost, _ = e if cap > 0 and r0 + cost - H[u] < dist[u]: dist[u] = r = r0 + cost - H[u] heappush(pq, (r, u)) prev_v[u] = v prev_e[u] = e # flow f doesn't exist if dist[t] == inf: return None for i in range(1, N + 1): H[i] += dist[i] g = f v = t while v != s: g = min(g, prev_e[v][1]) v = prev_v[v] f -= g res += g * H[t] v = t while v != s: e = prev_e[v] e[1] -= g e[-1][1] += g v = prev_v[v] return res N, M = map(int, input().split()) mcf = Mincostflow(N) for _ in range(M): a, b, c, d = map(int, input().split()) mcf.add_edge(a, b, 1, c) mcf.add_edge(b, a, 1, c) mcf.add_edge(a, b, 1, d) mcf.add_edge(b, a, 1, d) print(mcf.flow(1, N, 2)) if __name__ == '__main__': main()