#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
typedef long long ll;
//Version 1
int n,a[222]={},b[222]={};
int main(){
	freopen("ccyz.in","r",stdin);
	freopen("ccyz.out","w",stdout);
	
	ll i=0,j=0,num=0;
	cin>>n;
	for(i=0;i<n;i++){
		cin>>a[i]>>b[i];
//		cout<<a[i]<<b[i]<<endl;
	}
	i=0;//in
//	cout<<n<<endl;
	if(a[i]==0){
		cout<<b[i]<<endl;
		return 0;
	}
	do {
		i++;
		num=0;
		for(j=0;j<n;j++){
			if((i/a[j]*a[j]+b[j])==i)
				num++;
		}
	} while(num<n);
	cout<<i<<endl;
	return 0;
}