#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

// using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")


#ifndef LIBRA_OTHER_INT128_H_
#define LIBRA_OTHER_INT128_H_

#include <stdio.h>
#include <iostream>

constexpr unsigned __int128 toUInt128(const char *s) {
  unsigned __int128 x = 0;
  for (; *s; ++s) x = x * 10 + (*s - '0');
  return x;
}
constexpr __int128 toInt128(const char *s) {
  if (*s == '-') return -toInt128(s + 1);
  __int128 x = 0;
  for (; *s; ++s) x = x * 10 + (*s - '0');
  return x;
}
unsigned __int128 inUInt128() {
  static char buf[41];
  scanf("%s", buf);
  return toUInt128(buf);
}
__int128 inInt128() {
  static char buf[41];
  scanf("%s", buf);
  return toInt128(buf);
}

void out(unsigned __int128 x) {
  static char buf[41];
  int len = 0;
  do { buf[len++] = '0' + static_cast<int>(x % 10); } while (x /= 10);
  for (int i = len; --i >= 0; ) putchar(buf[i]);
}
void out(__int128 x) {
  if (x < 0) {
    putchar('-');
    out(-static_cast<unsigned __int128>(x));
  } else {
    out(static_cast<unsigned __int128>(x));
  }
}
std::ostream &operator<<(std::ostream &os, unsigned __int128 x) {
  static char buf[41];
  int len = 0;
  do { buf[len++] = '0' + static_cast<int>(x % 10); } while (x /= 10);
  for (int i = len; --i >= 0; ) os << buf[i];
  return os;
}
std::ostream &operator<<(std::ostream &os, __int128 x) {
  if (x < 0) {
    os << '-' << -static_cast<unsigned __int128>(x);
  } else {
    os << static_cast<unsigned __int128>(x);
  }
  return os;
}

#endif  // LIBRA_OTHER_INT128_H_

using INT = __int128;


// Minimum cost flow by successive shortest paths.
// Assumes that there exists no negative-cost cycle.
// TODO: Check the range of intermediate values.
template <class Flow, class Cost> struct MinCostFlow {
  // Watch out when using types other than int and long long.
  static constexpr Flow FLOW_EPS = 1e-10L;
  static constexpr Flow FLOW_INF = std::numeric_limits<Flow>::max();
  static constexpr Cost COST_EPS = 1e-10L;
  static constexpr Cost COST_INF = std::numeric_limits<Cost>::max();

  int n, m;
  vector<int> ptr, nxt, zu;
  vector<Flow> capa;
  vector<Cost> cost;

  explicit MinCostFlow(int n_) : n(n_), m(0), ptr(n_, -1) {}
  void ae(int u, int v, Flow w, Cost c) {
    assert(0 <= u); assert(u < n);
    assert(0 <= v); assert(v < n);
    assert(0 <= w);
    nxt.push_back(ptr[u]); zu.push_back(v); capa.push_back(w); cost.push_back( c); ptr[u] = m++;
    nxt.push_back(ptr[v]); zu.push_back(u); capa.push_back(0); cost.push_back(-c); ptr[v] = m++;
  }

  vector<Cost> pot, dist;
  vector<bool> vis;
  vector<int> pari;

  // cost slopes[j] per flow when flows[j] <= flow <= flows[j + 1]
  vector<Flow> flows;
  vector<Cost> slopes;

  // Finds a shortest path from s to t in the residual graph.
  // O((n + m) log m) time.
  //   Assumes that the members above are set.
  //   The distance to a vertex might not be determined if it is >= dist[t].
  //   You can pass t = -1 to find a shortest path to each vertex.
  void shortest(int s, int t) {
    using Entry = pair<Cost, int>;
    priority_queue<Entry, vector<Entry>, std::greater<Entry>> que;
    for (int u = 0; u < n; ++u) { dist[u] = COST_INF; vis[u] = false; }
    for (que.emplace(dist[s] = 0, s); !que.empty(); ) {
      const Cost c = que.top().first;
      const int u = que.top().second;
      que.pop();
      if (vis[u]) continue;
      vis[u] = true;
      if (u == t) return;
      for (int i = ptr[u]; ~i; i = nxt[i]) if (capa[i] > FLOW_EPS) {
        const int v = zu[i];
        if (!vis[v]) {
          const Cost cc = c + cost[i] + pot[u] - pot[v];
          if (dist[v] > cc) { que.emplace(dist[v] = cc, v); pari[v] = i; }
        }
      }
    }
  }

  // Finds a minimum cost flow from s to t of amount min{(max flow), limFlow}.
  //   Bellman-Ford takes O(n m) time, or O(m) time if there is no negative-cost
  //   edge, or cannot stop if there exists a negative-cost cycle.
  //   min{(max flow), limFlow} shortest paths if Flow is an integral type.
  pair<Flow, Cost> run(int s, int t, Flow limFlow = FLOW_INF) {
    assert(0 <= s); assert(s < n);
    assert(0 <= t); assert(t < n);
    assert(s != t);
    assert(0 <= limFlow);
    pot.assign(n, 0);
    for (; ; ) {
      bool upd = false;
      for (int i = 0; i < m; ++i) if (capa[i] > FLOW_EPS) {
        const int u = zu[i ^ 1], v = zu[i];
        const Cost cc = pot[u] + cost[i];
        if (pot[v] > cc + COST_EPS) { pot[v] = cc; upd = true; }
      }
      if (!upd) break;
    }
    dist.resize(n);
    vis.resize(n);
    pari.resize(n);
    Flow totalFlow = 0;
    Cost totalCost = 0;
    flows.clear(); flows.push_back(0);
    slopes.clear();
    for (; totalFlow < limFlow; ) {
      shortest(s, t);
      if (!vis[t]) break;
      for (int u = 0; u < n; ++u) pot[u] += min(dist[u], dist[t]);
      Flow f = limFlow - totalFlow;
      for (int v = t; v != s; ) {
        const int i = pari[v]; if (f > capa[i]) { f = capa[i]; } v = zu[i ^ 1];
      }
      for (int v = t; v != s; ) {
        const int i = pari[v]; capa[i] -= f; capa[i ^ 1] += f; v = zu[i ^ 1];
      }
      totalFlow += f;
      totalCost += f * (pot[t] - pot[s]);
      flows.push_back(totalFlow);
      slopes.push_back(pot[t] - pot[s]);
    }
    return make_pair(totalFlow, totalCost);
  }
};

////////////////////////////////////////////////////////////////////////////////


INT sq(INT r) { return r * r; }

int N, M;
int S, T;
vector<int> A, B, W, C;

int main() {
  for (; ~scanf("%d%d", &N, &M); ) {
    scanf("%d%d", &S, &T);
    --S;
    --T;
    A.resize(M);
    B.resize(M);
    W.resize(M);
    C.resize(M);
    for (int i = 0; i < M; ++i) {
      scanf("%d%d%d%d", &A[i], &B[i], &W[i], &C[i]);
      --A[i];
      --B[i];
    }
    
    MinCostFlow<INT, INT> mcf(N);
    for (int i = 0; i < M; ++i) {
      mcf.ae(A[i], B[i], W[i], C[i]);
    }
    mcf.run(S, T);
    const int len = mcf.slopes.size();
    const auto &X = mcf.flows;
    vector<INT> Y(len + 1, 0);
    for (int i = 0; i < len; ++i) Y[i + 1] = Y[i] + (X[i + 1] - X[i]) * mcf.slopes[i];
    const INT F = X[len];
// cerr<<"X = "<<X<<endl;
// cerr<<"Y = "<<Y<<endl;
    
    // dist^2 between (F, 0) and polyline
    INT pm = 1, qm = 0;
    auto check = [&](INT p, INT q) -> void {
      if (pm * q > p * qm) {
        pm = p;
        qm = q;
      }
    };
    
    for (int i = 0; i <= len; ++i) {
      check(sq(X[i] - F) + sq(Y[i] - 0), 1);
    }
    for (int i = 0; i < len; ++i) {
      if ((X[i + 1] - X[i]) * (F - X[i    ]) + (Y[i + 1] - Y[i]) * (0 - Y[i    ]) > 0 &&
          (X[i] - X[i + 1]) * (F - X[i + 1]) + (Y[i] - Y[i + 1]) * (0 - Y[i + 1]) > 0) {
        const INT p = sq((F - X[i + 1]) * (0 - Y[i]) - (F - X[i]) * (0 - Y[i + 1]));
        const INT q = sq(X[i + 1] - X[i]) + sq(Y[i + 1] - Y[i]);
        check(p, q);
      }
    }
    
    const INT g = __gcd(pm, qm);
    pm /= g;
    qm /= g;
    
    out(pm);
    printf("/");
    out(qm);
    puts("");
  }
  return 0;
}