#include <iostream>
#include <math.h>

using namespace std;

int main() {
  int n, a=0, cp = 0, s = 0, b=0;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> b;
    cp = b;
    a = 0;
    while (cp != 0) {
      a++;
      cp = cp / 10;
    }
    cp = b;
    if (a % 2 == 1) {
      for (int j = 0; j < (a-1)/2; j++) {
        cp = cp / 10;
      }
      s = s + (cp%10);
    }
  }
  cout << s;
  return 0;
}