#include <iostream>
#include<fstream>
using namespace std;
int main()
{
    int n,m,i,j,k,max=0,aa,bb;
    float sol=0,a,b,d,x,y;
    ifstream f("sate.in");
    ofstream g("sate.out");
    f>>n>>m>>x>>y;
    for(i=1;i<=n;i++)
    {
        f>>a>>b>>d;
        if(d>max)
        {
            max=d;
            aa=a;
            bb=b;

        }
    }
    g<<(int) (y-x)*max/(bb-aa);
    return 0;
}