
/*
			Saturday 01 May 2021 05:47:35 PM IST
					@uthor::astrainL3gi0N
*/

#include<bits/stdc++.h>
using namespace std;

typedef long long int ll;
typedef std::vector<int> vi;
typedef std::vector<ll> vll;
typedef std::pair<int,int> ii;
#define debg(x)	std::cerr<<(#x)<<" => "<<x<<'\n';
#define debgg(x,y)	std::cerr<<(#x)<<" => "<<x<<'\t'<<(#y)<<' '<<y<<'\n';
#define len(a) (int)(a).size()
#define all(x) x.begin(),x.end()
const int mod = 1000000007;
//const int mod = 998244353;

bool comp (int x, int y) {
    return x > y;
}
void printarr (int arr[], int n) {
    for(int i = 0; i < n; ++i)
        std::cerr<<arr[i]<<(i<n-1?' ':'\n');
}
template < typename T> void  printv (T &a) {
    for (auto it = a.begin(); it != a.end(); ++it)
        std::cerr<<*it<<' ';
    std::cerr<<'\n';
}
int gint() {
    int n;  cin>>n;
    return n;
}
    

const int maxn = 2009;
double ans;
double dt[maxn];
double ht[maxn];


void solve ()
{
    ans = 0;
    bool ok = 1;
    int n = gint();
    double d = gint();
    double h = gint();

    for (int i = 0; i < n;++i) {
        dt[i] = gint();
        ht[i] = gint();
    }
    n++;
    double slope=0 ,c=0;
    dt[n] = 0;
    
    for (int i = 0;ok &&  i < n;++i) {
        slope = (h-ht[i])/(d-dt[i]);
        c = h-slope*d;
        ok = 0;

        for (int j = 0; !ok && j < n;++j) {
            double temp = slope*dt[j]+c;

            ok = ht[j] > temp;

        }

    }
    ans = c;
    
    cout << setprecision(10) << fixed;
    std::cout<<ans;
    std::cout<<'\n';
}
void sol ()
{
    //test
}

int main ()
{
    //sol();return 0;
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(0);

    int testcases = 1;  
    //testcases = gint();
    for (int t = 0; t < testcases; ++t) {
        //cout<<"Case #"<<t+1<<": ";
        solve();
    }

    return 0;
}

#include <iostream>
using namespace std;

int main(void){
  int N, D, H;
  cin >> N>> D>>H;
  double b, d, h;
  double ans = 0.0;
  for( int i=0; i<N; ++i){
    cin >> d >>h;
    b = ((double)D*h - (double)H*d) / ((double)D-d);
    if(ans < b) ans = b;
  }
  cout<<ans;
  return 0;
}