#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <set>
#include <cmath>
#include <cstring>
#include <iomanip>
#include <random>
#include <chrono>
#include <queue>
#include <ctime>
#include <cassert>
using namespace std;
typedef long long ll;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
#define fs first
#define sc second
#define INF 1000000000
#define MOD 1000000007
#define EPS 0.00000001



int main() {
    int N; cin >> N;
    int x = 0;
    int y = 0;
    for(int i=0; i<N-1; i++){
        int a, b; cin >> a >> b;
        x+=a;
        y+=b;
    }
    
    cout << min(x, y) + 1 << endl;
    return 0;
}