Problem:
Score: 400 points

Problem Statement

To become a millionaire, M-kun has decided to make money by trading in the next N days. Currently, he has 1000 yen and no stocks - only one kind of stock is issued in the country where he lives.

He is famous across the country for his ability to foresee the future. He already knows that the price of one stock in the next N days will be as follows:

A_1 yen on the 1-st day, A_2 yen on the 2-nd day, ..., A_N yen on the N-th day.

In the i-th day, M-kun can make the following trade any number of times (possibly zero), within the amount of money and stocks that he has at the time.

Buy stock: Pay A_i yen and receive one stock.

Sell stock: Sell one stock for A_i yen.

What is the maximum possible amount of money that M-kun can have in the end by trading optimally?

Constraints

2 \leq N \leq 80

100 \leq A_i \leq 200

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_1 A_2 \cdots A_N

Output

Print the maximum possible amount of money that M-kun can have in the end, as an integer.

Sample Input 1

7
100 130 130 130 115 115 150

Sample Output 1

1685

In this sample input, M-kun has seven days of trading. One way to have 1685 yen in the end is as follows:

Initially, he has 1000 yen and no stocks.

Day 1: Buy 10 stocks for 1000 yen. Now he has 0 yen.

Day 2: Sell 7 stocks for 910 yen. Now he has 910 yen.

Day 3: Sell 3 stocks for 390 yen. Now he has 1300 yen.

Day 4: Do nothing.

Day 5: Buy 1 stock for 115 yen. Now he has 1185 yen.

Day 6: Buy 10 stocks for 1150 yen. Now he has 35 yen.

Day 7: Sell 11 stocks for 1650 yen. Now he has 1685 yen.

There is no way to have 1686 yen or more in the end, so the answer is 1685.

Sample Input 2

6
200 180 160 140 120 100

Sample Output 2

1000

In this sample input, it is optimal to do nothing throughout the six days, after which we will have 1000 yen.

Sample Input 3

2
157 193

Sample Output 3

1216

In this sample input, it is optimal to buy 6 stocks in Day 1 and sell them in Day 2, after which we will have 1216 yen.

Solution in C# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Numerics;
using static System.Console;
using static System.Math;
using CS_Contest.Loop;
using CS_Contest.Utils;
using static Nakov.IO.Cin;
using static CS_Contest.IO.IO;


namespace ContestCore {
    using bint = BigInteger;
    using Li = List<int>;
    using LLi = List<List<int>>;
    using Ll = List<long>;
    using ti3 = Tuple<int, int, int>;
    using ti2 = Tuple<int, int>;
    using tl3 = Tuple<long, long, long>;
    using ti4 = Tuple<int, int, int, int>;

    internal class Program {
        private static void Main(string[] args) {
            var sw = new StreamWriter(OpenStandardOutput()) {AutoFlush = false};
            SetOut(sw);
            Calc.Solve();
            Out.Flush();
        }

        public class Calc {
            public static void Solve() {
                var n = NextInt();
                var dp = new Map<int, Map<int, int>> {[0] = new Map<int, int> {[0] = 1000}};
                var max = 1000;
                for (var i = 0; i < n; i++) {
                    var ai = NextInt();
                    dp[i + 1] = new Map<int, int>();
                    foreach (var (k, v) in dp[i]) {
                        // k:=株の枚数
                        // v:=残金
                        for (var t = 0; t * ai <= v; t++) {
                            dp[i + 1][k + t] = v - t * ai;
                            max = Max(max, dp[i + 1][k + t]);
                        }

                        dp[i + 1][0] = v + k * ai;
                        max = Max(max, dp[i + 1][0]);
                    }
                }
                
                max.WL();
            }
        }
    }
}

namespace Nakov.IO {
    using System;
    using System.Text;
    using System.Globalization;

    public static class Cin {
        private static string NextToken() {
            var tokenChars = new StringBuilder();
            var tokenFinished = false;
            var skipWhiteSpaceMode = true;
            while (!tokenFinished) {
                var nextChar = Read();
                if (nextChar == -1) {
                    tokenFinished = true;
                }
                else {
                    var ch = (char) nextChar;
                    if (char.IsWhiteSpace(ch)) {
                        if (skipWhiteSpaceMode) continue;
                        tokenFinished = true;
                        if (ch == '\r' && Environment.NewLine == "\r\n") {
                            Read();
                        }
                    }
                    else {
                        skipWhiteSpaceMode = false;
                        tokenChars.Append(ch);
                    }
                }
            }

            var token = tokenChars.ToString();
            return token;
        }

        public static int NextInt() {
            var token = NextToken();
            return int.Parse(token);
        }

        public static long NextLong() {
            var token = NextToken();
            return long.Parse(token);
        }

        public static double NextDouble(bool acceptAnyDecimalSeparator = true) {
            var token = NextToken();
            if (acceptAnyDecimalSeparator) {
                token = token.Replace(',', '.');
                var result = double.Parse(token, CultureInfo.InvariantCulture);
                return result;
            }
            else {
                var result = double.Parse(token);
                return result;
            }
        }

        public static decimal NextDecimal(bool acceptAnyDecimalSeparator = true) {
            var token = NextToken();
            if (acceptAnyDecimalSeparator) {
                token = token.Replace(',', '.');
                var result = decimal.Parse(token, CultureInfo.InvariantCulture);
                return result;
            }
            else {
                var result = decimal.Parse(token);
                return result;
            }
        }

        public static BigInteger NextBigInteger(bool acceptAnyDecimalSeparator = true) {
            var token = NextToken();
            if (!acceptAnyDecimalSeparator) return BigInteger.Parse(token);
            token = token.Replace(',', '.');
            return BigInteger.Parse(token, CultureInfo.InvariantCulture);
        }
    }
}

namespace CS_Contest.Loop {
    [DebuggerStepThrough]
    public static class Loop {
        public static void REP(this int n, Action<int> act) {
            for (var i = 0; i < n; i++) {
                act(i);
            }
        }

        public static void ForeachWith<T>(this IEnumerable<T> ie, Action<int, T> act) {
            var i = 0;
            foreach (var item in ie) {
                act(i, item);
                i++;
            }
        }

        public static void Foreach<T>(this IEnumerable<T> ie, Action<T> act) {
            foreach (var item in ie) {
                act(item);
            }
        }
    }

    public class Generate {
        public static IEnumerable<int> Seq(int e) => Seq(0, e, 1);
        public static IEnumerable<int> Seq(int s, int e) => Seq(s, e, 1);

        public static IEnumerable<int> Seq(int s, int e, int a) {
            while (s != e) {
                yield return s;
                s += a;
            }
        }

        public static List<T> Repeat<T>(Func<int, T> result, int range) =>
            Enumerable.Range(0, range).Select(result).ToList();
    }
}

namespace CS_Contest.IO {
    using Li = List<int>;
    using Ll = List<long>;

    public static class IO {
        public static void WL(this object obj) => WriteLine(obj);
        public static void WL(this string obj) => WriteLine(obj);
        public static void WL<T>(this IEnumerable<T> list) => list.ToList().ForEach(x => x.WL());

        public static Li NextIntList() => ReadLine().Split().Select(int.Parse).ToList();

        public static Li NextIntList(int n) =>
            Enumerable.Repeat(0, n).Select(x => ReadLine()).Select(int.Parse).ToList();

        public static Ll NextLongList() => ReadLine().Split().Select(long.Parse).ToList();

        public static T Tee<T>(this T t, Func<T, string> formatter = null) {
            if (formatter == null) formatter = arg => arg.ToString();
            formatter(t).WL();
            return t;
        }

        public static void JoinWL<T>(this IEnumerable<T> @this, string sp = " ") => @this.StringJoin(sp).WL();
        public static void W(this object @this) => Write(@this);

        public static T[,] GetBox<T>(int h, int w, Func<int, int, T> getFunc) {
            var rt = new T[h, w];
            for (var i = 0; i < h; i++) {
                for (var j = 0; j < w; j++) {
                    rt[i, j] = getFunc(i, j);
                }
            }

            return rt;
        }
    }
}

namespace CS_Contest.Utils {
    using Li = List<int>;
    using Ll = List<long>;
    using bint = BigInteger;

    [DebuggerStepThrough]
    public static class Utils {
        public static bool AnyOf<T>(this T @this, params T[] these) where T : IComparable {
            return these.Contains(@this);
        }

        public static bool Within(int x, int y, int lx, int ly) => !(x < 0 || x >= lx || y < 0 || y >= ly);

        public static void Add<T1, T2>(this List<Tuple<T1, T2>> list, T1 t1, T2 t2) =>
            list.Add(new Tuple<T1, T2>(t1, t2));

        public static string StringJoin<T>(this IEnumerable<T> l, string separator = "") => string.Join(separator, l);

        public static Queue<T> ToQueue<T>(this IEnumerable<T> iEnumerable) {
            var rt = new Queue<T>();
            foreach (var item in iEnumerable) {
                rt.Enqueue(item);
            }

            return rt;
        }

        public static void Swap<T>(ref T x, ref T y) {
            var tmp = x;
            x = y;
            y = tmp;
        }

        public static List<Tuple<TKey, TValue>> ToTupleList<TKey, TValue>(this Map<TKey, TValue> @this) =>
            @this.Select(x => Tuple.Create(x.Key, x.Value)).ToList();


        public static Map<TKey, int> CountUp<TKey>(this IEnumerable<TKey> l) {
            var dic = new Map<TKey, int>();
            foreach (var item in l) {
                dic[item]++;
            }

            return dic;
        }

        public static int Count<T>(this IEnumerable<T> l, T target) => l.Count(x => x.Equals(target));

        public static IEnumerable<T> SkipAt<T>(this IEnumerable<T> @this, int at) {
            var enumerable = @this as T[] ?? @this.ToArray();
            for (var i = 0; i < enumerable.Count(); i++) {
                if (i == at) continue;
                yield return enumerable.ElementAt(i);
            }
        }

        public static int LowerBound<T>(this List<T> @this, T x) where T : IComparable {
            int lb = -1, ub = @this.Count;
            while (ub - lb > 1) {
                var mid = (ub + lb) >> 1;
                if (@this[mid].CompareTo(x) >= 0) ub = mid;
                else lb = mid;
            }

            return ub;
        }

        public static int UpperBound<T>(this List<T> @this, T x) where T : IComparable {
            int lb = -1, ub = @this.Count;
            while (ub - lb > 1) {
                var mid = (ub + lb) >> 1;
                if (@this[mid].CompareTo(x) > 0) ub = mid;
                else lb = mid;
            }

            return ub;
        }

        public static List<int> Imos(this IEnumerable<int> @this) {
            var rt = @this.ToList();
            for (var i = 0; i < rt.Count - 1; i++) rt[i + 1] += rt[i];
            return rt;
        }

        public static List<long> Imos(this IEnumerable<long> @this) {
            var rt = @this.ToList();
            for (var i = 0; i < rt.Count - 1; i++) rt[i + 1] += rt[i];
            return rt;
        }

        public static bool IsOdd(this long @this) => @this % 2 == 1;
        public static bool IsOdd(this int @this) => @this % 2 == 1;
        public static bool IsOdd(this bint @this) => @this % 2 == 1;
        public static bool IsMultiple(this int @this, int K) => @this % K == 0;
        public static bool IsMultiple(this long @this, long K) => @this % K == 0;

        public static long ToLong(int x) => (long) x;
    }


    public class Map<TKey, TValue> : Dictionary<TKey, TValue> {
        public Map() : base() {
        }

        public Map(int capacity) : base(capacity) {
        }

        public new TValue this[TKey index] {
            get {
                TValue v;
                return TryGetValue(index, out v) ? v : base[index] = default(TValue);
            }
            set { base[index] = value; }
        }
    }

    public static class MyMath {
        public static T EMin<T>(params T[] a) where T : IComparable<T> => a.Min();
        public static T EMax<T>(params T[] a) where T : IComparable<T> => a.Max();
    }
}