template<typename T>
class Stack{
    int n;
    T* arr;
    int m;
public:
    Stack(int n = 16){
        this->n = n;
        arr = new T[n];
        m = 0;
    }
    void push(T val){
        if(m == n - 1){
            cout << "Stack overflow" << endl;
            exit(1);
        }
        arr[m] = val;
        m++;
    }
    void pop(){
        if(!isEmpty()){
            m--;
        }else{
            exit(1);
        }

    }
    void top(){
        return arr[m];
    }
    bool isEmpty(){
        return m == 0 ? true : false;
    }
    int size(){
        return m;
    }
};