2 2
1 2 1 4 2 4
1 2 3 4 4 4
 2 2
1 2 0 9998 0 9999
2 1 0 9999 0 10000
 3 3
1 2 0 3 -4 7
2 3 -2 5 1 6
3 1 0 4 0 4
 2 2
1 2 0 3 0 3
2 1 0 4 0 4
 2 2
1 2 0 0 0 0
2 1 0 0 0 0
 5 10
4 3 -19 49 -11 65
4 4 50 12 -2 65
1 5 56 8 -5 76
5 1 -28 33 -38 49
4 2 0 0 2 9
4 2 0 0 14 8
3 1 26 67 15 85
5 3 -51 98 -44 99
1 3 -33 65 -20 65
3 4 30 6 -30 70
 5 10
4 3 -8 16 -29 72
4 4 -62 65 33 65
1 5 -58 97 -17 97
5 1 -5 10 -68 88
4 2 0 0 -9 60
4 2 0 0 -23 39
3 1 3 28 13 87
5 3 -1 25 -15 90
1 3 -12 33 6 94
3 4 -71 86 -39 86
 5 10
4 3 -1 5 -6 98
4 4 12 14 -43 98
1 5 -4 6 8 88
5 1 0 0 -9 100
4 2 0 0 6 50
4 2 0 0 -39 77
3 1 1 4 -1 100
5 3 -7 13 9 88
1 3 2 0 -7 100
3 4 2 0 3 88
 2 2
1 1 0 4 0 5
2 2 4 0 5 0
 2 2
1 2 0 4 0 4
2 1 0 4 0 4
 2 2
1 2 0 3 0 5
2 1 0 4 0 6

0
 1.0000000000
 0.2500000000
 0
 1.0000000000
 0.2121212000
 0.6666666000
 1.0000000000
 1.0000000000
 1.0000000000
 1.0000000000

#include <bits/stdc++.h>
using namespace std;
template <typename T>
void UMAX(T &a, T b) {
  a = (a > b ? a : b);
}
template <typename T>
void UMIN(T &a, T b) {
  a = (a < b ? a : b);
}
long long readint() {
  char c = getchar();
  long long ret = 0ll;
  bool neg = 0;
  while (!(c >= '0' && c <= '9')) {
    if (c == '-') neg = 1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    ret = ret * 10ll + (long long)(c - '0');
    c = getchar();
  }
  return neg ? -ret : ret;
}
void putint(long long v) {
  if (v < 0) {
    putchar('-');
    v = -v;
  }
  if (!v) {
    putchar('0');
    return;
  }
  if (v >= 10ll) putint(v / 10ll);
  putchar('0' + (v % 10ll));
}
const int S = 1002, T = 1003, inf = 50000000;
namespace flows {
struct edge {
  int v, r, id;
  long double f;
  edge(int V, int R, long double F, int _id) {
    v = V;
    r = R;
    f = F;
    id = _id;
  }
};
vector<edge> adj[1005];
int cur[1005], dis[1005];
void init() {
  int i;
  for (i = 0; i < 1005; ++i) {
    adj[i].clear();
  }
}
void addedge(int u, int v, long double f, int id, bool bi = 0) {
  adj[u].push_back(edge(v, (int)adj[v].size(), f, id));
  adj[v].push_back(edge(u, (int)adj[u].size() - 1, bi ? f : 0, -1));
}
void bfs() {
  queue<int> Q;
  Q.push(S);
  dis[S] = 0;
  while (!Q.empty()) {
    int i, cv = Q.front();
    Q.pop();
    for (i = 0; i < (int)adj[cv].size(); ++i) {
      if (adj[cv][i].f > 1e-8l && dis[adj[cv][i].v] == -1) {
        dis[adj[cv][i].v] = dis[cv] + 1;
        Q.push(adj[cv][i].v);
      }
    }
  }
}
long double dfs(int ver, long double cap) {
  if (ver == T) return cap;
  for (int &i = cur[ver]; i < (int)adj[ver].size(); ++i) {
    edge &E = adj[ver][i];
    if (E.f > 1e-8l && dis[E.v] > dis[ver]) {
      long double ret = dfs(E.v, min(cap, E.f));
      if (ret > 1e-8l) {
        E.f -= ret;
        adj[E.v][E.r].f += ret;
        return ret;
      }
    }
  }
  return 0;
}
long double maxflow() {
  long double ret = 0, dlt;
  while (1) {
    memset(dis, -1, sizeof(dis));
    memset(cur, 0, sizeof(cur));
    bfs();
    if (dis[T] == -1) return ret;
    dlt = 1;
    while (dlt > 1e-8l) {
      dlt = dfs(S, 1e9l);
      ret += dlt;
    }
  }
}
}  // namespace flows
int n, m;
vector<int> U, V, A, B, C, D;
long double calc(long double t) {
  flows::init();
  int i, j, k;
  long double suml = 0;
  for (i = 0; i < m; ++i) {
    int u = U[i], v = V[i], a = A[i], b = B[i], c = C[i], d = D[i];
    long double l = a * t + b, r = c * t + d;
    suml += l;
    flows::addedge(S, v, l, -1);
    flows::addedge(u, T, l, -1);
    flows::addedge(u, v, r - l, -1);
  }
  return flows::maxflow() - suml;
}
long double getpeak() {
  long double l = 0, r = 1;
  while (r - l > 1e-7l) {
    long double dif = (r - l) / 3;
    long double mid1 = l + dif, mid2 = l + dif + dif;
    if (calc(mid1) < calc(mid2))
      l = mid1;
    else
      r = mid2;
  }
  return l;
}
long double getR(long double peak) {
  long double l = peak, r = 1, mid;
  while (r - l > 1e-7l) {
    mid = (l + r) / 2;
    if (calc(mid) > -1e-8l)
      l = mid;
    else
      r = mid;
  }
  return l;
}
long double getL(long double peak) {
  long double l = 0, r = peak, mid;
  while (r - l > 1e-7l) {
    mid = (l + r) / 2;
    if (calc(mid) > -1e-8l)
      r = mid;
    else
      l = mid;
  }
  return l;
}
int main() {
  int i, j, k;
  n = readint();
  m = readint();
  for (i = 0; i < m; ++i) {
    int u = readint() - 1, v = readint() - 1, a = readint(), b = readint(),
        c = readint(), d = readint();
    U.push_back(u);
    V.push_back(v);
    A.push_back(a);
    B.push_back(b);
    C.push_back(c);
    D.push_back(d);
  }
  long double p = getpeak();
  printf("%.10f\n", (double)(getR(p) - getL(p)));
  return 0;
}
