Negative OSM_od conversion

Hi everyone,

I converted a shapefile into osm-format using JOSM. After conversion I end up with negative osm_ids. This is a big issue for me since I like to use the osm map to configure a graphhopper api to snap some gps data. But this is not possible when there are negative osm-ids (they get treated as empty markers). So the question is how can I turn these negative osm_ids into positive osm_ids?

Thank you in advance!

Best regards

MarDa93