var LFUCache = function(capacity) {
   this.storage = {};
   this.usage = {};
   this.size = 0;
   this.capacity = capacity;
 };

 LFUCache.prototype.get = function(key) {
   if (this.storage[key]) {
     this.usage[this.storage[key].uses]; // Before incrementing uses, we have to remove it from the array at the current usage value...
     this.storage[key].uses += 1;
     this.usage[this.storage[key].uses]; // ...then we have to push it onto the array for the new usage value.
     return this.storage[key].value;
   } else {
     return -1;
   }
 };

 LFUCache.prototype.put = function(key, value) {
   if (this.size < this.capacity) {
     if (this.storage[key]) {
       this.storage[key].value = value;
      //  this.storage[key].uses += 1;  // Problem doesn't specify whether reassignment counts as "use"; assuming NO.
     } else {
       this.storage[key] = { value: value, uses: 0 };
     }
   } else {

   }
  // else,
    // find least used value (key?)
      // we'll do this by checking possible usage values in the usage object, starting from 0
      // at the first usage array of length > 0, shift the key out of it and delete that key/value pair from storage
 };