import std.conv, std.functional, std.range, std.stdio, std.string; import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons; import core.bitop; class EOFException : Throwable { this() { super("EOF"); } } string[] tokens; string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; } int readInt() { return readToken.to!int; } long readLong() { return readToken.to!long; } real readReal() { return readToken.to!real; } bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } } bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } } int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; } int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); } int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); } // Dijkstra class MinCostFlow(Capa, Cost, Capa CAPA_EPS = 0) { int n, m; int[][] g; int[] as, bs; Capa[] capa; Cost[] cost, pot; Capa tof; Cost toc; this(int n) { this.n = n; m = 0; g = new int[][n]; as = []; bs = []; capa = []; cost = []; } int addEdge(int u, int v, Capa w, Cost c) { debug { writeln("addEdge ", u, " ", v, " ", w, " ", c); } const i = m; g[u] ~= m; as ~= u; bs ~= v; capa ~= w; cost ~= c; ++m; g[v] ~= m; as ~= v; bs ~= u; capa ~= 0; cost ~= -c; ++m; return i; } bool solve(int source, int sink, Capa flow) { pot = new Cost[n]; pot[] = 0; for (; ; ) { bool cont; foreach (u; 0 .. n) foreach (i; g[u]) if (capa[i] > CAPA_EPS) { const v = bs[i]; if (pot[v] > pot[u] + cost[i]) { pot[v] = pot[u] + cost[i]; cont = true; } } if (!cont) break; } auto dist = new Cost[n]; auto prei = new int[n]; auto vis = new bool[n]; for (tof = 0, toc = 0; tof + CAPA_EPS < flow; ) { alias Entry = Tuple!(Cost, "c", int, "u"); BinaryHeap!(Array!Entry, "a > b") que; dist[] = -1; prei[] = -1; vis[] = false; dist[source] = 0; prei[source] = -2; que.insert(Entry(0, source)); for (; !que.empty(); ) { const c = que.front.c; const u = que.front.u; que.removeFront; if (vis[u]) continue; vis[u] = true; foreach (i; g[u]) if (capa[i] > CAPA_EPS) { const v = bs[i]; if (vis[v]) continue; const cc = c + cost[i] + pot[u] - pot[v]; if (prei[v] == -1 || dist[v] > cc) { dist[v] = cc; prei[v] = i; que.insert(Entry(cc, v)); } } } if (!vis[sink]) return false; Capa f = flow - tof; for (int v = sink; v != source; ) { const i = prei[v]; if (f > capa[i]) f = capa[i]; v = as[i]; } for (int v = sink; v != source; ) { const i = prei[v]; capa[i] -= f; capa[i ^ 1] += f; v = as[i]; } tof += f; toc += f * (dist[sink] - pot[source] + pot[sink]); pot[] += dist[]; } return true; } } void main() { try { for (; ; ) { const N = readInt(); const M = readInt(); auto A = new int[M]; auto B = new int[M]; auto C = new long[M]; auto D = new long[M]; foreach (i; 0 .. M) { A[i] = readInt() - 1; B[i] = readInt() - 1; C[i] = readLong(); D[i] = readLong(); } auto mcf = new MinCostFlow!(int, long)(N); foreach (i; 0 .. M) { mcf.addEdge(A[i], B[i], 1, C[i]); mcf.addEdge(A[i], B[i], 1, D[i]); mcf.addEdge(B[i], A[i], 1, C[i]); mcf.addEdge(B[i], A[i], 1, D[i]); } mcf.solve(0, N - 1, 2); writeln(mcf.toc); } } catch (EOFException e) { } }