#include <bits/stdc++.h> using namespace std; int a[2000]; int head,tail; void push(int x) { a[head+1]=x; tail++; } int front() { return a[head]; } void pop() { if(head>tail) head++; } int size() { return tail-head; } bool empty() { if(head==tail) { return 1; }
} int main() {
}