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

#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)
#define P pair<int, int>
#define LP pair<ll, ll>


int main() {
  int n;
  cin >> n;
  vector<int> a(n), b(n);
  rep(i,n-1) cin >> a[i+1] >> b[i+1];
  int suma = 0, sumb = 0;
  rep(i,n) {
    suma += a[i];
    sumb += b[i];
  } 
  if (suma<=sumb) {
    cout << suma+1 << endl;
  } else  {
    cout << sumb+1 << endl;
  }

  
}