Sparse Matrix Multiplication

public class Solution {
    public int[][] multiply(int[][] A, int[][] B) {
        int aM = A.length, aN = A[0].length,  bN = B[0].length;
        int [][] result = new int[aM][bN];
        for (int i = 0; i < aM; i++) {
            for (int j = 0; j < aN; j++) {
                if (A[i][j] != 0) {
                    for (int k = 0; k < bN; k++) {
                        if (B[j][k] != 0) {
                            result[i][k] += A[i][j] * B[j][k];
                        }
                    }
                }
            }
        }
        return result;
    }
}