#include #include #include #include #include #include #include #include #define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl; #define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl; template inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; } using namespace std; typedef long long ll; typedef pair P; const ll INF = 1e18; struct edge{ int to; ll cap, cost; int rev; }; /** * 負のコストの辺がない場合のみ使える */ class MinCostFlow{ public: int V; // 頂点数 vector> G; MinCostFlow(int v){ V = v; G = vector>(v, vector()); dist = vector(v); preve = vector(v); prevv = vector(v); } void add_edge(int from, int to, ll cap, ll cost){ G[from].push_back((edge){to, cap, cost, G[to].size()}); G[to].push_back((edge){from, 0, -cost, G[from].size()-1}); } ll min_cost_flow(int s, int t, int f){ ll res = 0; while(f > 0){ fill(dist.begin(), dist.end(), INF); dist[s] = 0; priority_queue, greater

> que; que.push(P(0, s)); while(!que.empty()){ P top = que.top(); que.pop(); int v = top.second; ll d = top.first; if(dist[v] != d) continue; for(int i = 0; i < G[v].size(); i++){ edge &e = G[v][i]; if(e.cap > 0 && dist[e.to] > dist[v]+e.cost){ dist[e.to] = dist[v]+e.cost; prevv[e.to] = v; preve[e.to] = i; que.push(P(dist[e.to], e.to)); } } } if(dist[t] == INF){ return -1; } ll d = f; for(int v = t; v != s; v = prevv[v]){ d = min(d, G[prevv[v]][preve[v]].cap); } f -= d; res += d*dist[t]; for(int v = t; v != s; v = prevv[v]){ edge &e = G[prevv[v]][preve[v]]; e.cap -= d; G[v][e.rev].cap += d; } } return res; } private: vector dist; vector prevv, preve; }; int main(){ ios::sync_with_stdio(false); cin.tie(0); cout << setprecision(10) << fixed; int n, m; cin >> n >> m; MinCostFlow mcf(n); for(int i = 0; i < m; i++){ int u, v, c, d; cin >> u >> v >> c >> d; u--; v--; mcf.add_edge(u, v, 1, c); mcf.add_edge(v, u, 1, c); mcf.add_edge(u, v, 1, d); mcf.add_edge(v, u, 1, d); } cout << mcf.min_cost_flow(0, n-1, 2) << endl; }