Determinant

Source Code:
#include<stdio.h>
#include<stdlib.h>
int determinant(int** a)
{
    return a[0][0] * ((a[1][1]*a[2][2]) - (a[2][1]*a[1][2])) -a[0][1] * (a[1][0] * a[2][2] - a[2][0] * a[1][2]) + a[0][2] * (a[1][0] * a[2][1] - a[2][0] * a[1][1]);
} 
int main()
{
    int **arr, i, j;
    arr = (int*) malloc(sizeof(int) * 3);
    for (int i = 0; i < 3; i++)
        arr[i] = (int*) malloc(sizeof(int) * 3);
    for (i = 0; i < 3; i++) for (j = 0; j < 3; j++) scanf("%d", &arr[i][j]);
    printf("%d", determinant(arr));
    return 0;
}