int main(void) {


	int array[9] = { 1,2,3,4,6,7,8,9,10 };
	int i;
	for (i = 0;i <= 8;i++) {
		
		if (array[i+1] - array[i] == 2)                                                             
                 printf("%d\n", array[i] + 1);
	}
	return 0;
}