include<bits/stdc++.h>

using namespace std;

int main(){

int n,m;

while(cin >> n >> m,n||m){ vector garota1; vectorgarota2; int var=0, ant=0; for(int i=0;i<n;i++){ cin >> var; if(var!=ant){ garota1.push_back(var); } ant = var; }

for(int i=0;i<m;i++){
  cin >> var;
  if(var!=ant){
  garota2.push_back(var);
  }
  ant = var;
}

int cont=0;

if(garota2.size()<garota1.size()){
  for(int p:garota2){
    if(!binary_search(garota1.begin(),garota1.end(),p)){

      cont ++;
    }
  }
}

else{
  for(int p:garota1){
    if(!binary_search(garota2.begin(),garota2.end(),p)){
      cont ++;
    }
  }
}

cout << cont << endl;
garota1.clear();
garota2.clear();

}

return 0; }