/*
*
*   解説見てないお
*
*/
#include "bits/stdc++.h"
#define REP(i, n) for(int i = 0; i < int(n); i++)
#define FOR(i,n,m) for(int i = int(n); i < int(m); i++)
using namespace std;
typedef long long ll;
const int MOD = 1e9 + 7;
const int INF = 1e9 + 6;
const ll LLINF = 1e18 + 1;

int main() {
    int n; cin >> n;
    vector<pair<int, int>> p(n - 1);
    int sum_a = 0, sum_b = 0;
    REP(i, n - 1) {
        int a, b; scanf("%d %d", &a, &b);
        p[i].first = a;
        sum_a += a;
        p[i].second = b;
        sum_b += b;
    }
    cout << min(sum_a, sum_b) + 1 << endl;
    return 0;
}