#pragma GCC optimize(2)

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

inline ll read(){ll x=,f=;char c=getchar();for(;!isdigit(c);c=getchar()) if(c=='-') f=-;for(;isdigit(c);c=getchar()) x=x*+c-'';return x*f;}

const int maxn=;

const int M=1e7+;

const int INF=0x3f3f3f3f;

int main()

{

    ll n,sum1=,sum2=,i;

    ll a,b,t,m;

    cin>>n;

    sum1=;

    sum2=;

    for(i=;i<=n;i++)

    {

        scanf("%lld%lld",&a,&b);

        t=;

        if(sum1>a)

        {

           t=sum1/a;

           if(sum1%a!=)

                t++;

        }

        if(sum2>b)

        {

            m=sum2/b;

            if(sum2%b!=)

                m++;

            t=max(t,m);

        }

        sum1=a*t;

        sum2=b*t;

    }

    printf("%lld\n",sum1+sum2);

    return ;

}