private static void missingNumber(int[] array) {
		int startingTerm = array[0];
		int commonDiff = array[1] - startingTerm;
		
		int currentTerm = startingTerm;
		
		for (int i = 0; i < array.length; i++) {
			if (currentTerm != array[i]) {
				//System.out.println(currentTerm);
				//System.out.println(array[i]);
				System.out.println(currentTerm);
				break;
			} else {
				currentTerm += commonDiff;
			}
		}
	}