let maxLength = 0;

let solution = (str) => {

    let arr = str.split(",");

    for(let i=0; i<arr.length; i++){
        let newArr = [];
        for(let j=0; j<arr.length; j++){
            if(i!==j){
                newArr.push(arr[j]);
            }
        }
        traverse(arr[i], newArr, 1, arr[i]);
    }

    return maxLength;

};

let traverse = (current, left, length, chain) => {
    console.log("chain", chain);
    maxLength = Math.max(maxLength, length);
    for(let i=0; i<left.length; i++){
        let element = left[i];
        if(element[0] === current[2]){
            let newArr = [];
            for(let j=0; j<left.length; j++){
                if(i!==j){
                    newArr.push(left[j]);
                }
            }
            traverse(element, newArr, length+1, chain+"--"+element)
        }
    }
};