count.js

var count = function (data) {
    var left = 0,
        right = data.length - 1,
        result = 0;

    for (i = left + 1; i < right; i++) {
        if (data[i] < data[left])
            result += data[left] - data[i];
        else
            left = i;
    }

    return result;
};