unittest
{
	assert( [ "4 2 5", "1 2 5 7" ].parse.expand.solve == 11 );
	assert( [ "7 1 100", "40 43 45 105 108 115 124" ].parse.expand.solve == 84 );
	assert( [ "7 1 2", "24 35 40 68 72 99 103" ].parse.expand.solve == 12 );
}



import std.algorithm;
import std.conv;
import std.range;
import std.stdio;
import std.typecons;

void main()
{
	stdin.byLineCopy.parse.expand.solve.writeln;
}

auto parse( Range )( Range input )
if( isInputRange!Range && is( ElementType!Range == string ) )
{
	auto nab = input.front.split.to!( long[] );
	input.popFront;
	auto xs = input.front.split.to!( long[] );
	return tuple( nab[ 1 ], nab[ 2 ], xs );
}

auto solve( long a, long b, long[] xs )
{
	auto ans = 0L;
	for( auto i = 1L; i < xs.length; i++ )
	{
		ans += min( ( xs[ i ] - xs[ i - 1 ] ) * a, b );
	}
	return ans;
}
