diff --git a/neuronal_network.c b/neuronal_network.c
index 0ed8137..fdcbe08 100644
--- a/neuronal_network.c
+++ b/neuronal_network.c
@@ -147,7 +147,10 @@ Matrix* predict(Neural_Network* network, Matrix* image_data) {
 //void batch_train_network(Neural_Network* network, Image** images, int size);
 
 double relu(double input) {
-    return 1.0;
+    if (input < 0){
+        return 0.0;
+    }
+    return input;
     //TODO: relu formel
 }