#include <bits/stdc++.h>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}

int main() {
	int n = ri();
	n--;
	int a_sum = 0, b_sum = 0;
	for (int i = 0; i < n; i++) a_sum += ri(), b_sum += ri();
	std::cout << std::min(b_sum, a_sum) + 1 << std::endl;
	
	return 0;
}