#include <stack>

using std::stack;

class Queue {

public:

// Push element x to the back of queue.

void push(int x) {

if(this->empty())

{

stack1.push(x);

return;

}

while(!stack1.empty())

{

stack2.push(stack1.top());

stack1.pop();

}

stack1.push(x);

while(!stack2.empty())

{

stack1.push(stack2.top());

stack2.pop();

}

printf("Stack Size: %d.\n", stack1.size());

}

// Removes the element from in front of queue.

void pop(void) {

stack1.pop();

}

// Get the front element.

int peek(void) {

return stack1.top();

}

// Return whether the queue is empty.

bool empty(void) {

return stack1.empty() && stack2.empty();

}

private:

stack<int> stack1;

stack<int> stack2;

};