import std.stdio;

void main(){
	auto io = new IO();
	
	size_t N = io.rect!size_t(1)[0][0];
	writeln( N/5*2 + N/3*2 );
	
	return;
}
auto solve(){
}
unittest{
	
}

import std.stdio,std.conv,std.string;
import std.algorithm,std.array,std.math;

class IO
{
	T[] line( T = size_t , string token = " " )( size_t m = 1 ){
		T[] arr = [];
		foreach( i ; 0..m ){
			arr ~= this.read!T();
		}
		return arr;
	}
	T[][] rect( T = size_t , string token = " " )( size_t m = 1 ){
		T[][] arr = new T[][](m);
		foreach( i ; 0..m ){
			arr[i] = this.read!T(token);
		}
		return arr;
	}
	private T[] read( T = size_t )( string token = " " ){
		T[] arr;
		foreach( elm ; readln().chomp().split(token) ){
			arr ~= elm.to!T();
		}
		return arr;
	}
}