#include <stdio.h>
#define N 100000
#define Q 50000

int main() {
    
    int S[N],T[Q],i,n,q,count=0,left,right,mid;
    
    scanf("%d",&n);
    for(i=0; i<n; i++) scanf("%d",&S[i]);
    
    scanf("%d",&q);
    for(i=0; i<q; i++) scanf("%d",&T[i]);
    
    for(i=0; i<q; i++) {
        left = 0;
        right = n;
        
        while(left<right) {
            mid = (left+right)/2;
            
            if(S[mid]==T[i]) {
                count++;
                break;
            }
            else if(T[i]<S[mid]) right = mid;
            else left = mid+1;
        }
    }
    
    printf("%d\n",count);
    
    return 0;
}