#define _GLIBCXX_DEBUG 1
#define _GLIBCXX_DEBUG_PEDANTIC 1
#define _FORTIFY_SOURCE 2

#include <bits/stdc++.h>

#define all(x) (x).begin(),(x).end()

using vi = std::vector<int>;

int main() {
    vi left = {1,2,3};
    vi right = {3,1,2};
    vi res;
    std::merge(all(left), all(right), std::back_inserter(res));
}