var maxEnvelopes = function(envelopes) {
    var count = 0;
    if (envelopes.length === 0) { return count; }
    count++;
    if (envelopes.length === 1) { return count; }
    //sort by width of each envelope, sort by heigth of each envelope for matching widths
    envelopes.sort((a, b) => {
        if (a[0] < b[0]) {
            return -1;
        }
        if (a[0] > b[0]) {
            return 1;
        }
        if (a[0] === b[0]) {
            if (a[1] < b[1]) {
            return -1;
            }
            if (a[1] > b[1]) {
                return 1;
            }
            if (a[1] === b[1]) {
                return 0;
            }
        }
    })
    //check in order of envelopes for next width that is >
    //then compare height too
    //if yes, count++ and reset the item to check against

    var current_item = envelopes[0];

    for (var i = 1; i < envelopes.length; i++) {
        if (envelopes[i][0] > current_item[0]) {
            if (envelopes[i][1] > current_item[1]) {
                count++;
                current_item = envelopes[i];
            }
        }
    }
    return count;
};

//recursion needed but didn't get this working
//     var recurse = function(envelopes) {
//         //base case, reach end of envelopes and return 0 or 1 based on size
//         //recurse case, test for each item in the array
//         //if match, then recurse with the rest of the array, count + return

//         var count = 0;
//         if (envelopes.length === 0) { return count; }
//         count++;
//         if (envelopes.length === 1) { return count; }
//         var current_item = envelopes[0];
//         var maxCount = count;

//         for (var i = 1; i < envelopes.length; i++) {
//             if (envelopes[i][0] > current_item[0]) {
//                 if (envelopes[i][1] > current_item[1]) {
//                     count += recurse(envelopes.slice(i));
//                 }
//             }
//             if (count > maxCount) {
//                 maxCount = count;
//             }
//         }
//         return maxCount;
//     }