using System;

namespace AtCoder
{
    static class Solver
    {
        static IO io = new IO();

        public static void Solve()
        {
            io.ReadSplit();
            int N = io.Int();
            int A = io.Int();
            int B = io.Int();

            int[] h = new int[N];
            for (int i = 0; i < N; ++i)
            {
                io.Read();
                h[i] = io.Int();
            }

            io.WriteLine(Ans(N, A, B, h).ToString());
        }

        public static long Ans(int N, int A, int B, int[] h)
        {
            long left = 0;
            long right = int.MaxValue;

            while (left < right)
            {
                long mid = left + (right - left) / 2;
                if (Enough(mid, N, A, B, h))
                {
                    right = mid;
                }
                else
                {
                    left = mid + 1;
                }
            }
            return right;
        }

        public static bool Enough(long count, int N, int A, int B, int[] h)
        {
            long count_sum = 0;
            for (int i = 0; i < N; ++i)
            {
                long rest_hp = h[i] - count * B;
                if (0 < rest_hp)
                {
                    count_sum += (long)Math.Ceiling(((decimal)rest_hp / (A - B)));
                }
            }
            if (count_sum <= count)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}
namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            Solver.Solve();
        }
    }
    class IO
    {
        private string[] _Inputs;
        private int _Index;
        public void Read()
        {
            _Inputs = new string[1];
            _Inputs[0] = Console.ReadLine();
            _Index = 0;
        }
        public void ReadSplit()
        {
            _Inputs = Console.ReadLine().Split(' ');
            _Index = 0;
        }
        public string String()
        {
            return _Inputs[_Index++];
        }
        public string[] String(int xCount)
        {
            string[] rv = new string[xCount];
            Array.Copy(_Inputs, _Index, rv, 0, xCount);
            _Index += xCount;
            return rv;
        }
        public int Int()
        {
            return int.Parse(_Inputs[_Index++]);
        }
        public int[] Int(int xCount)
        {
            int[] rv = new int[xCount];
            for (int i = 0; i < xCount; ++i)
            {
                rv[i] = int.Parse(_Inputs[_Index++]);
            }
            return rv;
        }
        public long Long()
        {
            return long.Parse(_Inputs[_Index++]);
        }
        public long[] Long(int xCount)
        {
            long[] rv = new long[xCount];
            for (int i = 0; i < xCount; ++i)
            {
                rv[i] = long.Parse(_Inputs[_Index++]);
            }
            return rv;
        }
        public void Write(string xStr)
        {
            Console.Write(xStr);
        }
        public void WriteLine(string xStr)
        {
            Console.WriteLine(xStr);
        }
    }
}

Measured memory_bytes: 17344