#include <iostream>
#include <cmath>
using namespace std;
int main(){
  int n;cin>>n;
  if(n==2){
    cout << 1 << endl;
    return 0;
  }
  int a[n];
  int b[n];
  a[0] = 0;
  b[0] = 0;
  int a_sm = 0;
  int b_sm = 0;
  for(int i = 1; n > i; i++){
    cin>>a[i]>>b[i];
    a_sm += a[i];
    b_sm += b[i];
  }
  cout << min(a_sm,b_sm)+1 << endl;
}