diff --git a/pdb-api/src/main/java/org/lucares/pdb/api/StringCompressor.java b/pdb-api/src/main/java/org/lucares/pdb/api/StringCompressor.java
index 8ca82c4..49cb05e 100644
--- a/pdb-api/src/main/java/org/lucares/pdb/api/StringCompressor.java
+++ b/pdb-api/src/main/java/org/lucares/pdb/api/StringCompressor.java
@@ -34,7 +34,7 @@ public class StringCompressor {
 
     public int putString(final String string) {
 
-        return usip.computeIfAbsent(string, s -> usip.getHighestInteger() + 1);
+        return usip.computeIfAbsent(string);
     }
 
     public int putStringFromBytes(final byte[] bytes, final int start, final int endExclusive,