#include <bits/stdc++.h>
using namespace std;
namespace mcmf {
const int MAX = 31000;
const long long INF = 1LL << 60;
long long cap[MAX], flow[MAX], cost[MAX], dis[MAX];
int n, m, s, t, Q[MAX * 10], adj[MAX], link[MAX], last[MAX], from[MAX],
    visited[MAX];
void init(int nodes, int source, int sink) {
  m = 0, n = nodes, s = source, t = sink;
  for (int i = 0; i <= n; i++) last[i] = -1;
}
void addEdge(int u, int v, long long c, long long w) {
  adj[m] = v, cap[m] = c, flow[m] = 0, cost[m] = +w, link[m] = last[u],
  last[u] = m++;
  adj[m] = u, cap[m] = 0, flow[m] = 0, cost[m] = -w, link[m] = last[v],
  last[v] = m++;
}
bool spfa() {
  int i, j, x, f = 0, l = 0;
  for (i = 0; i <= n; i++) visited[i] = 0, dis[i] = INF;
  dis[s] = 0, Q[l++] = s;
  while (f < l) {
    i = Q[f++];
    for (j = last[i]; j != -1; j = link[j]) {
      if (flow[j] < cap[j]) {
        x = adj[j];
        if (dis[x] > dis[i] + cost[j]) {
          dis[x] = dis[i] + cost[j], from[x] = j;
          if (!visited[x]) {
            visited[x] = 1;
            if (f && rand() & 7)
              Q[--f] = x;
            else
              Q[l++] = x;
          }
        }
      }
    }
    visited[i] = 0;
  }
  return (dis[t] != INF);
}
pair<long long, long long> solve() {
  int i, j;
  long long mincost = 0, maxflow = 0;
  while (spfa()) {
    long long aug = INF;
    for (i = t, j = from[i]; i != s; i = adj[j ^ 1], j = from[i]) {
      aug = min(aug, cap[j] - flow[j]);
    }
    for (i = t, j = from[i]; i != s; i = adj[j ^ 1], j = from[i]) {
      flow[j] += aug, flow[j ^ 1] -= aug;
    }
    maxflow += aug, mincost += aug * dis[t];
  }
  return make_pair(mincost, maxflow);
}
}  // namespace mcmf
const int N = 105;
long long INF = 1e9;
int bal[N];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  int source = 0, sink = n + 1;
  mcmf::init(n + 3, source, sink);
  long long ans = 0;
  for (int i = 1; i <= m; i++) {
    int u, v, c, f;
    cin >> u >> v >> c >> f;
    bal[u] -= f;
    bal[v] += f;
    if (f < c) {
      mcmf::addEdge(u, v, c - f, 1);
      mcmf::addEdge(u, v, INF, 2);
      mcmf::addEdge(v, u, f, 1);
    } else {
      ans += f - c;
      mcmf::addEdge(v, u, f - c, 0);
      mcmf::addEdge(v, u, c, 1);
      mcmf::addEdge(u, v, INF, 2);
    }
  }
  for (int i = 1; i <= n; i++) {
    if (bal[i] > 0)
      mcmf::addEdge(source, i, bal[i], 0);
    else
      mcmf::addEdge(i, sink, -bal[i], 0);
  }
  mcmf::addEdge(n, 1, INF, 0);
  mcmf::addEdge(1, n, INF, 0);
  long long xx = mcmf::solve().first;
  ans += xx;
  cout << ans << endl;
}
