#include <stdio.h>
int main(void)
{
    int n,S[100000],q,T[50000],C=0,i,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-1;
        while(left<right)
        {
            mid=(left+right)/2;
            if(S[mid]==T[i])
            {
                C++; break;
            }
            else if(S[mid]>T[i]) right=mid-1;
            else if(S[mid]<T[i]) left=mid+1;
        }
    }
    
    printf("%d\n",C);
    
    return 0;
}

