#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
LL n,num[12],yu[12],ok=0,mxid,mxnum=-1;
int main()
{
	freopen("ccyz.in","r",stdin);
	freopen("ccyz.out","w",stdout);
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>num[i]>>yu[i];
        if(num[i]>mxnum)
        {
            mxnum=num[i];mxid=i;
        }
    }
    LL j=yu[mxid];
    while(ok==0)
    {
        ok=1;
        for(int i=1;i<=n;i++)
        {
            if(j%num[i]!=yu[i])
            {
                ok=0;
                j+=num[mxid];
                break;
            }
        }
    }
    cout<<j;
}