diff --git a/lib/rawmerge.hpp b/lib/rawmerge.hpp
index 37b16c9..900470a 100644
--- a/lib/rawmerge.hpp
+++ b/lib/rawmerge.hpp
@@ -65,6 +65,12 @@ public:
     return this->timeseries_;
   }
 
+  // get number of channels
+  unsigned long int get_num_channels()
+  {
+    return this->channels_.size();
+  }
+
   // get array representation i-th channel
   std::vector<double> get_channel(long unsigned int chidx)
   {
diff --git a/src/main.cpp b/src/main.cpp
index fb8c75a..f7aa51b 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -36,6 +36,8 @@ int main(int argc, char* argv[])
   raw_merger eatmea;
   eatmea.add_channel(rawfile,true);
   eatmea.add_channel("smp/VehicleSpeed_HS.raw",true);
+  eatmea.add_channel("smp/VehicleSpeed_HS.raw",true);
+  eatmea.add_channel("smp/Rangerover_Evoque_F-RR534_2019-05-07/Temp_Disc_FR.raw",true);
 
   //eatraw.show_markers();