[
    {
        "min_n": 6,
        "max_n": 10,
        "variant": "solvable"
    },
    {
        "min_n": 3,
        "max_n": 20,
        "variant": "solvable"
    },
    {
        "min_n": 3,
        "max_n": 6,
        "variant": "solvable"
    },
    {
        "min_n": 5,
        "max_n": 15,
        "variant": "random"
    }
]