#include <bits/stdc++.h>
using namespace std;

#define REP(i, n) for(int (i) = 0; (i) < (n); (i)++)
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) < (b) ? (a) : (b))

typedef long long ll;

int main(void){
	int n;
	cin >> n;

	int sum[2] = {};
	REP(i, n-1){
		int a, b;
		cin >> a >> b;
		sum[0] += a;
		sum[1] += b;
	}

	cout << MIN(sum[0], sum[1])+1 << endl;

	return 0;
}