int longestSubsequence(int N, int arr[])
{
    int dp[1002] = {0}; 

    int temp;
    for(int i = 1; i <= N; i++){
        temp = max(dp[arr[i - 1] - 1], dp[arr[i - 1] + 1]) + 1;
        dp[arr[i - 1]] = max(dp[arr[i - 1]], temp);
    }

    int mx = 0;
    for(int i = 0; i <= 1000; i++){
        mx = max(mx, dp[i]);
    }

    return mx;
}