diff --git a/label_smooth.py b/label_smooth.py
index 86e9878..22815dd 100644
--- a/label_smooth.py
+++ b/label_smooth.py
@@ -36,7 +36,7 @@ def forward(self, logits, label):
             ignore = label.eq(self.lb_ignore)
             n_valid = ignore.eq(0).sum()
             label[ignore] = 0
-            lb_pos, lb_neg = 1. - self.lb_smooth, self.lb_smooth / num_classes
+            lb_pos, lb_neg = 1. - self.lb_smooth, self.lb_smooth / (num_classes - 1)
             lb_one_hot = torch.empty_like(logits).fill_(
                 lb_neg).scatter_(1, label.unsqueeze(1), lb_pos).detach()
 
@@ -61,7 +61,7 @@ class LSRCrossEntropyFunctionV2(torch.autograd.Function):
     def forward(ctx, logits, label, lb_smooth, lb_ignore):
         # prepare label
         num_classes = logits.size(1)
-        lb_pos, lb_neg = 1. - lb_smooth, lb_smooth / num_classes
+        lb_pos, lb_neg = 1. - lb_smooth, lb_smooth / (num_classes - 1)
         label = label.clone().detach()
         ignore = label.eq(lb_ignore)
         n_valid = ignore.eq(0).sum()