problem = {
    "start": ["at door", "on floor", "has ball", "hungry", "chair at door"],
    "finish": ["not hungry"],
    "ops": [
        {
            "action": "climb on chair",
            "preconds": ["chair at middle room", "at middle room", "on floor"],
            "add": ["at bananas", "on chair"],
            "delete": ["at middle room", "on floor"]
        },
        {
            "action": "push chair from door to middle room",
            "preconds": ["chair at door", "at door"],
            "add": ["chair at middle room", "at middle room"],
            "delete": ["chair at door", "at door"]
        },
        {
            "action": "walk from door to middle room",
            "preconds": ["at door", "on floor"],
            "add": ["at middle room"],
            "delete": ["at door"]
        },
        {
            "action": "grasp bananas",
            "preconds": ["at bananas", "empty handed"],
            "add": ["has bananas"],
            "delete": ["empty handed"]
        },
        {
            "action": "drop ball",
            "preconds": ["has ball"],
            "add": ["empty handed"],
            "delete": ["has ball"]
        },
        {
            "action": "eat bananas",
            "preconds": ["has bananas"],
            "add": ["empty handed", "not hungry"],
            "delete": ["has bananas", "hungry"]
        }
    ]
}