class MinStack {
public:
    /** initialize your data structure here. */
    vector<int>s1,s2;
    MinStack() {

    }

    void push(int x) {
        s1.push_back(x);

        if(s2.empty() || x <= getMin())s2.push_back(x);

    }

    void pop() {
        if(s1.back() == getMin())s2.pop_back();
        s1.pop_back();

    }

    int top() {
        return s1.back();


    }

    int getMin() {
        return s2.back();

    }
};

/**
 * Your MinStack object will be instantiated and called as such:
 * MinStack* obj = new MinStack();
 * obj->push(x);
 * obj->pop();
 * int param_3 = obj->top();
 * int param_4 = obj->getMin();
 */