diff --git a/unet_demo.py b/unet_demo.py
index 5ae1bb0..6d34508 100644
--- a/unet_demo.py
+++ b/unet_demo.py
@@ -81,6 +81,11 @@ def __init__(self, in_channels, out_channels, n_class, kernel_size,
 
         self.down3 = DownConv(4 * out_channels, 8 * out_channels, kernel_size,
                               padding, stride)
+        self.down4 = DownConv(8 * out_channels, 16 * out_channels, kernel_size,
+                              padding, stride)
+        
+        self.up4 = UpConv(16 * out_channels, 8 * out_channels, 8 * out_channels,
+                          kernel_size, padding, stride)
 
         self.up3 = UpConv(8 * out_channels, 4 * out_channels, 4 * out_channels,
                           kernel_size, padding, stride)
@@ -99,8 +104,10 @@ def forward(self, x):
         x1 = self.down1(x)
         x2 = self.down2(x1)
         x3 = self.down3(x2)
+        x4 = self.down4(x3)
         # Decoder
-        x_up = self.up3(x3, x2)
+        x_up = self.up4(x4, x3)
+        x_up = self.up3(x_up, x2)
         x_up = self.up2(x_up, x1)
         x_up = self.up1(x_up, x)
         x_out = F.log_softmax(self.out(x_up), 1)