// dfmt off
T lread(T=long)(){return readln.chomp.to!T;}T[] lreads(T=long)(long n){return iota(n).map!((_)=>lread!T).array;}
T[] aryread(T=long)(){return readln.split.to!(T[]);}void arywrite(T)(T a){a.map!text.join(' ').writeln;}
void scan(L...)(ref L A){auto l=readln.split;foreach(i,T;L){A[i]=l[i].to!T;}}alias sread=()=>readln.chomp();
void dprint(L...)(lazy L A){debug{auto l=new string[](L.length);static foreach(i,a;A)l[i]=a.text;arywrite(l);}}
static immutable MOD=10^^9+7;alias PQueue(T,alias l="b<a")=BinaryHeap!(Array!T,l);import std;
// dfmt on

void main()
{
    long N = lread();
    long a = 1, b = 1;
    foreach (_; 0 .. N)
    {
        long T, A;
        scan(T, A);

        long ng = 0;
        long ok = (1000000000000000000 + max(T, A) - 1) / max(T, A);
        dprint((1000000000000000000 - 1 + max(T, A)), ok, T, A);
        while (abs(ng - ok) > 1)
        {
            long m = (ok + ng) / 2;
            long x = T * m;
            long y = A * m;
            if (x < a || y < b)
            {
                ng = m;
            }
            else
            {
                ok = m;
            }
        }
        a = T * ok;
        b = A * ok;
        dprint(ok, a, b);
    }
    writeln(a + b);
}
