public String put(String key, String value) {

		//Checking if the key appears either in the file or the cache
		if(containsKey(key)) {

			//Saves the old value
			String oldValue = get(key);

			//replaces and returns
			tm.put(key, value);
			return oldValue;
		}

		//Does not exist, so add to the cache
		else {
			tm.put(key, value);
			totalWords++;
		}
		return value;
	}