module app;

import core.bitop;

import std.algorithm;
import std.array;
import std.bigint;
import std.container.rbtree;
import std.conv;
import std.stdio;
import std.string;
import std.traits;

struct Input
{
	int n, x, t;
}

void parseInput(T)(out Input input, T adapter)
{
	with (input)
	{
		adapter.readf!"%d "(n);
		adapter.readf!"%d "(x);
		adapter.readf!"%d"(t);
	}
}

struct Output
{
}

auto main2(Input* input)
{
	with (input)
	{
		return (n + x - 1) / x * t;
	}
}

alias retType = ReturnType!main2;
static if (!is(retType == void))
{
	unittest { writeln("begin unittest"); }
	auto _placeholder_ = ReturnType!main2.init;

	unittest // example1
	{
		string example =
`20 12 6`;
		if (example.empty) return;
		Input input = void;
		parseExample(input, example);
		auto result = main2(&input);
		printResult(result);
		assert(result == 12);
	}

	unittest // example2
	{
		string example =
`1000 1 1000`;
		if (example.empty) return;
		Input input = void;
		parseExample(input, example);
		auto result = main2(&input);
		printResult(result);
		assert(result == 1000000);
	}

	unittest // example3
	{
		string example =
``;
		if (example.empty) return;
		Input input = void;
		parseExample(input, example);
		auto result = main2(&input);
		printResult(result);
		assert(result == _placeholder_);
	}

	unittest { writeln("end unittest"); }

	void parseExample(out Input input, string example)
	{
		parseInput(input, new StringAdapter(example));
	}
}

class StdinAdapter
{
	// readf!"%s"は使えない
	// https://issues.dlang.org/show_bug.cgi?id=19820
	uint readf(alias format, A...)(auto ref A args) { return std.stdio.readf!format(args); }
	string readln() { return std.stdio.readln().strip(); }
}

class StringAdapter
{
	import std.format;
	string _s;
	this(string input) { _s = input; }
	uint readf(alias format, A...)(auto ref A args) { return _s.formattedRead!format(args); }
	string readln()
	{
		auto i = _s.countUntil("\n");
		if (i == -1) i = _s.length;
		string ret = _s[0..i];
		_s = _s[i..$];
		return ret;
	}
}

void printResult(T)(T result)
{
	static if (isFloatingPoint!T) writefln("%f", result);
	else writeln(result);
}

void main()
{
	Input input = void;
	parseInput(input, new StdinAdapter());
	static if (is(retType == void))
		main2(&input);
	else
	{
		auto result = main2(&input);
		printResult(result);
	}
}
