/* Piyush Sharma*/
 
#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
 
int main()
{
    ll testcase = 1;
    // ll testcase;
    // cin >> testcase;
 
    while (testcase > 0)
    {
        double n, D, H;
        cin >> n >> D >> H;
 
        double maxVal = INT_MIN;
        double backup = 0 * 1.0000;
 
        while ( n > 0 ) {
            double d, h;
            cin >> d >> h;
 
            double res = double((h*1.0) - ((d*1.0)*(((H-h)*1.0)/(D-d))));
            if ( res >= maxVal ) {
                maxVal = res;
            } 
            n--;
        }

        if ( maxVal <= 0 ) {
            cout << setprecision(16) << backup;
        }
        else {
            cout << setprecision(16) << maxVal;
        }
        
        testcase--;
    }
    return 0;
}
#include <bits/stdc++.h>
using namespace std;
#define rep(i,t,n) for(int64_t i=t;i<n;i++)
#define Sort(a) sort(a.begin(),a.end())
#define rSort(a,n,m) sort(a.begin()+n-1,a.begin()+m)
#define Reverse(a) reverse(a.begin(),a.end())
#define rReverse(a,n,m) reverse(a.begin()+n-1,a.begin()+m)
#define MOD 1000000007
#define sign(i) -1*pow(-1,i)
#define vi(A,N,i)  vector<int64_t> A(N,i)
#define vs(A,N,i)  vector<string> A(N,i)
#define vb(A,N,i)  vector<bool> A(N,i)
#define INF ((1LL<<62)-(1LL<<31))
//((a+b+c)-max(a,max(b,c))-min(a,min(b,c)))

/*template <class T>

}*/


//cout << fixed << setprecision(桁数);

int64_t def_str(string x,string y){
  int64_t def=0;
  rep(i,0,(int64_t)x.size()){
    if(x[i]!=y[i]){
      def++;
    }
  }
  return def;
}

int main() {
  //int64_t a,b,c,d,e,f,g,h,hi,ans=0,now_ans=0,mlt_ans=1;
  double a,b,c,d,e,f,ans=0,now_ans=0,mlt_ans=1;
  string x,y,z;
  char s,t,u;
  bool frag=false,frag1=false,frag2=false;
  vector<int64_t> A{},B{},C{},D{};
  vector<string> Cg{},Dg{};
  vector<char> E{},F{};
  vector<bool> G(26,false);
  cin>>a>>b>>c;
  //cin>>x;
  //cin>>s>>t;////////////////////////
  rep(i,0,a){
    cin>>d>>e;
    f=-(b*(c-e)/(b-d))+c;
    ans=max(ans,f);
  }
  cout << fixed << setprecision(20);
  cout<<ans;
}