void merge(int l, int m, int r)
{
    //char** output=malloc(curn*sizeof(char*));

    //output=arr;
    int i, j, k;
    int n1 = m - l + 1;
    int n2 = r - m;


    char** L=malloc(n1*sizeof(char*));
    char** R=malloc(n2*sizeof(char*));


    for (i = 0; i < n1; i++)
    {
        L[i] = arr[l + i];
    }
    for (j = 0; j < n2; j++)
    {
        R[j] = arr[m + 1 + j];
    }


    i = 0; // Initial index of first subarray
    j = 0; // Initial index of second subarray
    k = l; // Initial index of merged subarray
    while (i < n1 && j < n2)
    {
        if (cmp2(R[j], L[i]))
        {
            arr[k] = L[i];
            i++;
        }
        else
        {
            arr[k] = R[j];
            j++;
        }
        k++;
    }


    while (i < n1)
    {
        arr[k] = L[i];
        i++;
        k++;
    }


    while (j < n2)
    {
        arr[k] = R[j];
        j++;
        k++;
    }
}