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class Solution
{
public:
void push(int node) {
stack1.push(node);
}

int pop() {
int a=0;
if(!stack2.empty())
{
a=stack2.top();
stack2.pop();
}
else
{
while(!stack1.empty())
{
int temp=stack1.top();
stack2.push(temp);
stack1.pop();
}
a=stack2.top();
stack2.pop();
}
return a;
}

private:
stack<int> stack1;
stack<int> stack2;
};