#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n, o;
    string s;
    cin >> n >> s;
    o = s[n - 1] - '0';
    for (int i = 0; i < n - 1; i++) o += (s[i] == '0' ? 0 : s[i] - 47);
    cout << o << endl;
  }
  return 0;
}
