//
// ABC046C
// URL : https://atcoder.jp/contests/abc046/tasks/abc046_c
// 
using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;

namespace AtCoder
{
    class ABC046C
    {
        class Ratio
        {
            public long T;
            public long A;
            public Ratio() { T = A = 0; }
            public Ratio(long _T, long _A)
            {
                T = _T;
                A = _A;
            }
        }
        static void Main(string[] args)
        {
            preprocess();

            long N = long.Parse(Console.ReadLine());
            var RatioList = new List<Ratio>((int)N);
            for (int i = 0; i < N; ++i)
            {
                long[] inputLongArray = Console.ReadLine().Split(' ').Select(_inputStr => long.Parse(_inputStr)).ToArray();
                RatioList.Add(new Ratio(inputLongArray[0], inputLongArray[1]));
            }

            //初期の票数を最初の比率で与える
            long T_Vote = RatioList[0].T;
            long A_Vote = RatioList[0].A;
            //i回目の確認では、Ti,Aiの比率の倍数かつ、i-1回目の確認より0票以上互いに多く票が集まっている
            for (int i = 1; i < RatioList.Count; ++i)
            {
                //i-1回目の確認より0票以上互いに多く票が集まっている必要がある
                //つまり
                //T_Vote <= x * RatioList[i].T && A_Vote <= x * RatioList[i].A
                //を満たす最小のxを見つける
                //このようなxは、上を式変形して
                //T_Vote / RatioList[i].T <= x && A_Vote / RatioList[i].A <= x
                //&&はMath.Maxと考えられる(小さい方に合わせると、T,Aどっちかが条件を満たさない)

                var extimateX_T = (T_Vote + RatioList[i].T - 1) / RatioList[i].T;
                var extimateX_A = (A_Vote + RatioList[i].A - 1) / RatioList[i].A;

                var x = (long)(Math.Max(extimateX_T, extimateX_A));
                T_Vote = x * RatioList[i].T;
                A_Vote = x * RatioList[i].A;
                //Console.WriteLine("{0},vote {1}   {2}", i, T_Vote, A_Vote);
            }

            long sum = T_Vote + A_Vote;
            Console.WriteLine(sum.ToString());
            Console.Out.Flush();
        }

        //---------------------------------------------------------------------------------
        /// <summary>
        /// 
        /// </summary>
        public static void preprocess()
        {
            //出力高速化
            var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            Console.SetOut(sw);
        }


        /// <summary>
        /// 与えられた数が素数かどうかを計算する
        /// </summary>
        /// <param name="num">対象数</param>
        /// <returns>true:素数, false:素数ではない(合成数)</returns>
        public static bool isPrime(int num)
        {
            if (num < 2) return false;
            else if (num == 2) return true;
            else if (num % 2 == 0) return false;

            double sqrtNum = Math.Sqrt(num);
            for (int i = 3; i <= sqrtNum; i += 2)
            {
                if (num % i == 0)
                {
                    return false;
                }
            }
            return true;
        }

        /// <summary>
        /// 順列mPnを計算する
        /// </summary>
        /// <param name="m"></param>
        /// <param name="n"></param>
        /// <returns></returns>
        public static long Permutation(long m, long n)
        {
            long ret = 1;
            for(var i = 0; i < n; ++i)
            {
                ret *= m - i;
            }
            return ret;
        }
        /// <summary>
        /// 組み合わせmCnを計算する
        /// </summary>
        /// <param name="m"></param>
        /// <param name="n"></param>
        /// <returns></returns>
        public static long Combination(long m, long n)
        {
            if(m == n || n == 0)
            {
                return 1;
            }
            long ans = 1;
            for(var i = 0; i <= n; ++i)
            {
                ans *= (m - i + 1) / i;
            }
            return ans;
        }

        static long Gcd(long m, long n)
        {
            if (n == 0) return m;
            return Gcd(n, m % n);
        }

        static long Lcm(long m, long n)
        {
            var gcd = Gcd(m, n);
            //return (m * n) / gcd;
            return m / gcd * n;//桁あふれ対策
        }
    }
}



Measured memory_bytes: 13396