#include <stdio.h>
#define nmax 1024
#define max(a,b) (a>b)?a:b
using namespace std;
int n,m,a[nmax],b[nmax],c[nmax][nmax],i,j,sub[nmax],nr=1;

int main()
{
    FILE *f=fopen("subsir.in","r"),*g=fopen("subsir.out","w");
    fscanf(f,"%d%d",&n,&m);
    for(i=1;i<=n;i++)fscanf(f,"%d",&a[i]);
    for(i=1;i<=m;i++)fscanf(f,"%d",&b[i]);
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
        if(a[i]==b[j]){c[i][j]=c[i-1][j-1]+1;sub[c[i][j]]++;}
    else c[i][j]=max(c[i-1][j],c[i][j-1]);
    for(i=1;sub[i]!=0;i++)nr*=sub[i];


    fprintf(g,"%d\n",nr);


    return 0;
}