import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int sumA = 0;
		int sumB = 0;
		for (int i = 0; i < n - 1; i++) {
		    sumA += sc.nextInt();
		    sumB += sc.nextInt();
		}
		int count = Math.min(sumA, sumB) + 1;
		System.out.println(count);
	}
}