#include <bits/stdc++.h>

#pragma region my_template

struct Rep {
  struct I {
    int i;
    void operator++() { ++i; }
    int operator*() const { return i; }
    bool operator!=(I o) const { return i < *o; }
  };
  const int l_, r_;
  Rep(int l, int r) : l_(l), r_(r) {}
  Rep(int n) : Rep(0, n) {}
  I begin() const { return {l_}; }
  I end() const { return {r_}; }
};
struct Per {
  struct I {
    int i;
    void operator++() { --i; }
    int operator*() const { return i; }
    bool operator!=(I o) const { return i > *o; }
  };
  const int l_, r_;
  Per(int l, int r) : l_(l), r_(r) {}
  Per(int n) : Per(0, n) {}
  I begin() const { return {r_ - 1}; }
  I end() const { return {l_ - 1}; }
};

template <class F>
struct Fix : private F {
  Fix(F f) : F(f) {}
  template <class... Args>
  decltype(auto) operator()(Args&&... args) const {
    return F::operator()(*this, std::forward<Args>(args)...);
  }
};

template <class T = int>
T scan() {
  T res;
  std::cin >> res;
  return res;
}

template <class T, class U = T>
bool chmin(T& a, U&& b) {
  return b < a ? a = std::forward<U>(b), true : false;
}
template <class T, class U = T>
bool chmax(T& a, U&& b) {
  return a < b ? a = std::forward<U>(b), true : false;
}

#ifndef LOCAL
#define DUMP(...) void(0)
template <int OnlineJudge, int Local>
constexpr int OjLocal = OnlineJudge;
#endif

using namespace std;

#define ALL(c) begin(c), end(c)

#pragma endregion

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  cout << fixed << setprecision(20);
  int n = scan();
  double du = scan();
  double hu = scan();
  double ans = 0;
  while (n--) {
    double d = scan();
    double h = scan();
    double cur = hu - (hu - h) / (du - d) * du;
    chmax(ans, cur);
  }
  cout << ans << '\n';
}

/*#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2,fma")*/
// only when really needed

/* GNU G++17 7.3.0: No long long for faster code
   GNU G++17 9.2.0 (64 bit, msys 2): Long long only for faster code */
 
#include <bits/stdc++.h>
  
#define for1(i,a,b) for (int i = a; i <= b; i++)
#define for2(i,a,b) for (int i = a; i >= b; i--)
#define int long long

#define sz(a) (int)a.size()
#define pii pair<int,int>
 
/*
__builtin_popcountll(x) : Number of 1-bit
__builtin_ctzll(x) : Number of trailing 0
*/
 
#define PI 3.1415926535897932384626433832795
#define INF 1000000000000000000
#define MOD 1000000007
#define MOD2 1000000009
#define EPS 1e-6

using namespace std;

int n;
double d, h, a[1005], b[1005];

signed main() {
    
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

    // freopen("cf.inp", "r", stdin);
    // freopen("cf.out", "w", stdout);

    cin >> n >> d >> h;

    for1(i,1,n) cin >> a[i] >> b[i];

    double l = 0.0, r = 1000.0;

    for1(i,1,100) {

    	bool flag = true;
    	double m = (l + r)/2;
    	for1(i,1,n) {

    		double br = m + (h - m)*(a[i] / d);
    		if (br + EPS < b[i]) {
    			flag = false;
    			break;
    		}

    	}

    	if (flag) r = m;
    	else l = m;

    }

    cout << fixed << setprecision(3) << l;
    
}