unittest
{
	assert( [ "3" ].solve == 3 );
	assert( [ "100" ].solve == 473 );
	assert( [ "1000000" ].solve == 13969985 );
}



import std.conv;
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 = input.front.to!( long );
	
	auto ans = 0L;
	foreach( a; 1L .. n + 1 )
	{
		foreach( b; 1L .. n + 1 )
		{
			if( n <= a * b ) break;
			ans++;
		}
	}
	return ans;
}
