//Normal #define _GLIBCXX_DEBUG #define ll long long #include using namespace std; using Graph = vector>; void print(auto a){ cout << a; } void prints(auto a){ cout << a << " "; } void prints(){ cout << " "; } void printl(auto a){ cout << a << endl; } void printl(){ cout << endl; } void fix(int n){ cout << fixed << setprecision(n); } int main(){ int N; cin >> N; vector X(N); for(int i = 0; i < N; i++) cin >> X[i]; sort(X.begin(), X.end()); int ans = X[0]; for(int i = 1; i < N; i++){ if(X[i-1]+1 != X[i]) ans += X[i]; } printl(ans); return 0; }