{
  "analysis": "The cost is still way too high. I need to use relative cursor movements much more efficiently. The key insight is to process rows in order and use CR + vertical moves to navigate between rows, and CUF/CUB within rows.",
  "plan": "Calculate the cost using relative cursor movements (CR, CUD, CUF) instead of absolute positioning. This should be much more efficient.",
  "commands": [
    {
      "keystrokes": "python3 << 'PYEOF'\nimport struct\nfrom collections import defaultdict\n\nwith open('/app/frames.tza', 'rb') as f:\n    f.read(4)\n    w, h = struct.unpack('<HH', f.read(4))\n    n_frames, max_bytes = struct.unpack('<II', f.read(8))\n    frames = [f.read(w*h) for _ in range(n_frames)]\n\ndef find_runs(changes):\n    runs = []\n    if not changes:\n        return runs\n    run_start = changes[0]\n    run_end = changes[0]\n    for c in changes[1:]:\n        if c == run_end + 1:\n            run_end = c\n        else:\n            runs.append((run_start, run_end))\n            run_start = run_end = c\n    runs.append((run_start, run_end))\n    return runs\n\n# Calculate cost using relative movements\ndef rel_move_cost(from_r, from_c, to_r, to_c):\n    if from_r == to_r and from_c == to_c:\n        return 0\n    if from_r == to_r:\n        dc = to_c - from_c\n        if dc > 0:\n            return 4 + len(str(dc))  # ESC[nC\n        else:\n            return 4 + len(str(-dc))  # ESC[nD\n    # Different rows: CR + vertical + horizontal\n    cost = 1  # CR\n    dr = to_r - from_r\n    if dr > 0:\n        cost += 4 + len(str(dr))  # ESC[nB\n    elif dr < 0:\n        cost += 4 + len(str(-dr))  # ESC[nA\n    if to_c > 1:\n        cost += 4 + len(str(to_c - 1))  # ESC[nC from col 1\n    return cost\n\n# Frame 0: write non-space runs\ntotal_cost = 0\ncursor_r, cursor_c = 1, 1\nfor r in range(h):\n    row = frames[0][r*w:(r+1)*w]\n    non_space = [c for c in range(w) if row[c] != 32]\n    runs = find_runs(non_space)\n    for start, end in runs:\n        total_cost += rel_move_cost(cursor_r, cursor_c, r+1, start+1) + (end - start + 1)\n        cursor_r, cursor_c = r+1, end+2  # after writing\ntotal_cost += 1  # delimiter\nprint(f'Frame 0 cost: {total_cost}')\n\n# Subsequent frames\nfor i in range(1, n_frames):\n    # Find changed rows\n    changed_rows = [r for r in range(h) if frames[i-1][r*w:(r+1)*w] != frames[i][r*w:(r+1)*w]]\n    if not changed_rows:\n        total_cost += 1  # just delimiter\n        continue\n    \n    for r in changed_rows:\n        prev_row = frames[i-1][r*w:(r+1)*w]\n        curr_row = frames[i][r*w:(r+1)*w]\n        changes = [c for c in range(w) if prev_row[c] != curr_row[c]]\n        runs = find_runs(changes)\n        \n        # Cost of EL + rewrite\n        cost_erase = rel_move_cost(cursor_r, cursor_c, r+1, 1) + 4 + w\n        \n        # Cost of partial updates\n        cost_partial = 0\n        for start, end in runs:\n            cost_partial += rel_move_cost(cursor_r, cursor_c, r+1, start+1)\n            cursor_r, cursor_c = r+1, end+2\n        cost_partial += len(changes)\n        \n        # Choose cheaper\n        if cost_erase <= cost_partial:\n            total_cost += rel_move_cost(cursor_r, cursor_c, r+1, 1) + 4 + w\n            cursor_r, cursor_c = r+1, w+1\n        else:\n            total_cost += cost_partial\n    total_cost += 1  # delimiter\n\nprint(f'Total cost: {total_cost}')\nprint(f'Budget: {max_bytes}')\nprint(f'Diff: {total_cost - max_bytes}')\nPYEOF\n",
      "duration": 5.0
    }
  ]
}