#include <string>
#include <vector>
#include <algorithm>
#include <map>
#include <set>
#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;

class SwapAndArithmetic {
  public:
    string able(vector <int> x);
};

string SwapAndArithmetic::able(vector <int> x)
{
  return "";
}