function surfaceArea(A) {
  if (A.length === 1 && A[0] === 1) return 6;

  let surface = 0;

  for (let row = 0; row < A.length; row++) {
    const currentRow = A[row];
    for (let col = 0; col < currentRow.length; col++) {
      const height = currentRow[col];

      // Add top and bottom surfaces
      surface += 2;

      // Add side surfaces
      const neighbors = [
        row > 0 ? A[row - 1][col] : 0, // Front
        row < A.length - 1 ? A[row + 1][col] : 0, // Back
        col > 0 ? currentRow[col - 1] : 0, // Left
        col < currentRow.length - 1 ? currentRow[col + 1] : 0, // Right
      ];

      for (const neighbor of neighbors) {
        surface += Math.max(0, height - neighbor);
      }
    }
  }

  return surface;
}