#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    int N, sum = 0, minr = 10001;
    int x, y;
    cin >> N;
    for (int i = 0; i < N; i++) {
        cin >> x >> y;
        if (x > y) {
            sum += x;
        } else {
            sum += y;
        }
        if (((int)abs(x - y) % 2 == 1) && (abs(x - y) < minr)) {
            minr = abs(x - y);
        }
    }
    if (sum % 2 == 1) {
        cout << sum;
    } else if (sum % 2 == 0 && minr != 10001) {
        cout << sum - minr;
    } else {
        cout << 0;
    }
    return 0;
}