#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main()
{
    ios::sync_with_stdio(0);
    int n;
    cin >> n;
    long long mn=1e9, sum = 0;
    for (int i = 0; i < n; i++) {
        long long dop1, dop2;
        cin >> dop1 >> dop2;
        sum += max(dop1, dop2);
        if ((dop1 - dop2) % 10 != 0) {
            mn = min(mn, abs(dop1 - dop2));
        }
    }
    if (sum % 10 == 5) {
        sum -= mn;
    }
    cout <<sum<<endl;
}