unittest
{
	assert( [ "20 12 6" ].solve == 12 );
	assert( [ "1000 1 1000" ].solve == 1000000 );
}



import std.conv;
import std.format;
import std.range;
import std.stdio;

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

auto solve( Range )( Range input )
if( isInputRange!Range && is( ElementType!Range == string ) )
{
	auto n = 0L;
	auto x = 0L;
	auto t = 0L;
	input.front.formattedRead!"%s %s %s"( n, x, t );
	
	return ( n + x - 1 ) / x * t;
}
