import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        long times = Long.parseLong(reader.readLine());
        Map<Long, Boolean> map = new HashMap<>();

        for (int i = 0; i < times; i++) {
            StringTokenizer tokenizer = new StringTokenizer(reader.readLine());
            float a = Float.parseFloat(tokenizer.nextToken());
            int b = Integer.parseInt(tokenizer.nextToken());

            for (int j = 1; j <= b; j++) {
                long l = (long) (a * j);
                if (!map.containsKey(l)) {
                    map.put(l, true);
                } else {
                    map.remove(l);
                }
            }
        }

        System.out.println(map.keySet().iterator().next());
    }
}