6. Вырубка леса

using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using System.Threading.Tasks;

namespace region
{
    class Program
    {
        const ulong inf = 1000000000000000000;
        const string Name = "forest";
        #region Read
        static string[] Split(string s)
        {
            return s.Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
        }
        static int ReadInt()
        {
            return int.Parse(Console.ReadLine());
        }
        static long ReadLong()
        {
            return long.Parse(Console.ReadLine());
        }
        static double ReadDouble()
        {
            return double.Parse(Console.ReadLine());
        }
        static int[] ReadArrayL()
        {
            int l = ReadInt();
            return ReadArray(Split(Console.ReadLine()), l);
        }
        static int[] ReadArray()
        {
            return ReadArray(Split(Console.ReadLine()));
        }
        static int[] ReadArray(int count)
        {
            return ReadArray(Split(Console.ReadLine()), count);
        }
        static int[] ReadArray(string[] args)
        {
            return ReadArray(args, args.Length);
        }
        static int[] ReadArray(string[] args, int count)
        {
            int[] res = new int[count];
            for (int i = 0; i < count; i++)
            {
                res[i] = int.Parse(args[i]);
            }
            return res;
        }
        #endregion
        #region Init
        static void InitIO(string path)
        {
            Console.SetIn(new StreamReader(path + ".in"));
            Console.SetOut(new StreamWriter(path + ".out"));
        }
        static void InitDebug(string path)
        {
            Console.SetIn(new StreamReader(path + ".in"));
        }
        #endregion

        static ulong Get(ulong days, ulong a, ulong k)
        {
            ulong dk = days / k;
            ulong ans = (days - dk) * a;

            if (ans > inf) return inf;
            else return ans;
        }
        static void Main()
        {
            InitIO(Name);
            // InitDebug(Name);

            ulong[] args = (from arg in Console.ReadLine().Split(' ')
                            select ulong.Parse(arg)).
                            ToArray();

            ulong a = args[0];
            ulong k = args[1];
            ulong b = args[2];
            ulong m = args[3];
            ulong x = args[4];

            ulong ans = 0;
            ulong min = 1;
            ulong max = (inf / (a + b)) + (inf / (k + m)) + 1000;
            max = Math.Min(inf, 2 * max);
            while(min <= max)
            {
                ulong c = (min + max) / 2;

                ulong v1 = Get(c, a, k);
                ulong v2 = Get(c, b, m);

                ulong v = v1 + v2;
                if (v < x)
                {
                    min = c + 1;
                }
                else
                {
                    ans = c;
                    max = c - 1;
                }
            }

            Console.WriteLine(ans);
            Console.Out.Flush();
            Console.Out.Close();
        }
    }
}