using System;
using System.Collections.Generic;
using System.Linq;
using BitArray = System.Collections.BitArray;
using BigInteger = System.Numerics.BigInteger;
using TextReader = System.IO.TextReader;

namespace AtCoderProject
{
    public class Program
    {
        public object Calc()
        {
            var D = consoleReader.Int;
            var G = consoleReader.Int / 100;
            var tasks = new TaskGroup[D];
            for (int i = 0; i < D; i++)
                tasks[i] = new TaskGroup { score = i + 1, num = consoleReader.Int, bonus = consoleReader.Int / 100 };

            var allCount = tasks.Sum(t => t.num);
            var dp = new int[allCount + 1];

            foreach (var t in tasks)
            {
                var olddp = dp.ToArray();
                for (int p = 1; p < t.num; p++)
                    for (int i = p; i < dp.Length; i++)
                    {
                        var s = olddp[i - p] + t.score * p;
                        if (dp[i] < s) dp[i] = s;
                    }
                for (int i = t.num; i < dp.Length; i++)
                {
                    var s = olddp[i - t.num] + t.score * t.num + t.bonus;
                    if (dp[i] < s) dp[i] = s;
                }
            }

            for (int i = 1; i < dp.Length; i++)
                if (dp[i] >= G)
                    return i;

            return 0;
        }
        struct TaskGroup
        {
            public int score;
            public int bonus;
            public int num;
        }

        #region いつもの
        private readonly ConsoleReader consoleReader;
        public Program(ConsoleReader consoleReader) { this.consoleReader = consoleReader; }
        static void Main() => Console.WriteLine(new Program(new ConsoleReader(Console.In)).Calc()); static string AllLines<T>(IEnumerable<T> source) => string.Join("\n", source);
        #endregion
    }

#pragma warning disable
    public class ConsoleReader
    {
        private string[] line = Array.Empty<string>();
        private int linePosition;
        private TextReader textReader;
        public ConsoleReader(TextReader tr) { textReader = tr; }
        public int Int => int.Parse(String);
        public long Long => long.Parse(String);
        public double Double => double.Parse(String);
        public string String
        {
            get
            {
                if (linePosition >= line.Length)
                {
                    linePosition = 0;
                    line = textReader.ReadLine().Split();
                }
                return line[linePosition++];
            }
        }
        public class SplitLine
        {
            private string[] splited;
            public SplitLine(ConsoleReader cr) { splited = cr.textReader.ReadLine().Split(); }
            public int[] Int => String.Select(x => int.Parse(x)).ToArray();
            public long[] Long => String.Select(x => long.Parse(x)).ToArray();
            public double[] Double => String.Select(x => double.Parse(x)).ToArray();
            public string[] String => splited;
        }
        public SplitLine Split => new SplitLine(this);
        public class RepeatReader
        {
            ConsoleReader cr; int count;
            public RepeatReader(ConsoleReader cr, int count) { this.cr = cr; this.count = count; }
            public IEnumerable<T> Select<T>(Func<ConsoleReader, T> func) { for (int i = 0; i < count; i++) yield return func(cr); }
            public IEnumerable<string> String { get { for (int i = 0; i < count; i++) yield return cr.String; } }
            public IEnumerable<int> Int { get { for (int i = 0; i < count; i++) yield return cr.Int; } }
            public IEnumerable<double> Double { get { for (int i = 0; i < count; i++) yield return cr.Double; } }
        }
        public RepeatReader Repeat(int count) => new RepeatReader(this, count);
    }
}

Measured memory_bytes: 13396