let max = -Infinity;
    for(let i=0;i<=3;i++){   
        for(let j= 0;j<=3;j++){
            
        let  sum= arr[i][j]+arr[i][j+1]+arr[i][j+2]
                      +arr[i+1][j+1]+
                arr[i+2][j]+arr[i+2][j+1]+arr[i+2][j+2]
                     
            if(sum>max){
                max=sum
            }
        }
    }
    return max