#include <iostream>
#include <algorithm>
using namespace std;
#define MAXN 500000
int v[ MAXN + 1 ];
int n, a, b;
bool canbesplit( int sz, int a, int b )
{
int num = sz / a;
int dif = sz % a;
if( a == b && dif != 0 )
{
return false;
}
else if( a == b )
{
return true;
}
else
{
return ( b - a ) * num > dif;
}
}
bool check( int val )
{
int index = 1, prevind = 0;
while( index < n )
{
if( v[ index ] - v[ index - 1 ] > val )
{
if( canbesplit( index - prevind, a, b ) == false )
{
return false;
}
prevind = index;
}
index++;
}
return canbesplit( n - prevind, a, b );
}
int bsearch( )
{
int left = 0, right = v[ n - 1 ] - v[ 0 ] + 1;
int answ = right;
while( left <= right )
{
int mid = ( left + right ) / 2;
if( check( mid ) == true )
{
answ = mid;
right = mid - 1;
}
else
{
left = mid + 1;
}
}
return answ;
}
int main()
{
cin >> n >> a >> b;
for( int i = 0; i < n; i++ )
{
cin >> v[ i ];
}
std::sort( v, v + n );
cout << bsearch( );
return 0;
}
