int main(){

int n; cin >> n; vector<int> v(n); for (int i = 0; i < n; ++i) cin >> v[i]; sort(v.begin(), v.end()); int ans = 0, currmax = 0, currmin = INT_MAX; for (int i = 0; i < n-1; ++i){ if ((v[i+1] - v[i]) > 1){ if (currmax == 0) currmax = max(v[i], v[i+1]); // first time else{ // second time and more times ans += min(currmin, currmax); // take the smaller one to get the maximum sum of the pairings of numbers currmin = INT_MAX, currmax = 0; // reset for next pairing if ((v[i+1] - v[i]) > 2) { // there is a gap between two numbers which is bigger than 2 -> add it to current max and min for next pairing int midpoint = (v[i] + v[i+1])/2 ; // find the midpoint between two numbers with gap bigger than 2 currmin = min(midpoint, min(v[