public class Solution {
    List<int> list = new List<int>();    
    public int LongestConsecutive(int[] nums) {
        
        for(int i = 0; i < nums.Length; i++){
            if(!list.Contains(nums[i])){
                list.Add(nums[i]);
            }
        }

        int max = 0;
        int num = 0;
        int length = 0;

        foreach(int i in list){
            num = i;
            length = 1;
            if(!list.Contains(num-1)){
                while(list.Contains(num+1)){
                    num++;
                    length++;
                }
            }
            max = Math.Max(length,max);
        }

        return max;
    }
}