Forth

#include <bits/stdc++.h>

#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()

using namespace std;
using ll = long long;

const int inf = 1e9;
const ll LLInf = 1e18;

int main() {
    cin.tie(0)->sync_with_stdio(0);
    int x; cin >> x;

    if (x == 1) {
        cout << "2\nDUP DROP\n";
        return 0;
    }

    vector<string> ans;

    int am = 0;
    while (x > 1) {
        ans.push_back("DUP");
        if (x & 1) {
            ans.push_back("DUP"); am++;
        }
        ans.push_back("+");
        x >>= 1;
    }
    for (int _ = 0; _ < am; ++_) ans.push_back("+");

    cout << sz(ans) << "\n";
    for (auto s : ans) cout << s << " ";
    cout << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED