#include <bits/stdc++.h>
using namespace std;

const int N = 5000;

int n,m,a[N],b[N],mapp[N][N],res,used[N];

void dfs(int x,int y){
    if(x>n)return ;
    if(mapp[x][y]<0){
        return ;
    }else{
        if(y==m){
            if(!used[x])res++;
            used[x]++;
            return ;
        }
        if(x+1<=n)dfs(x+1,y);
        dfs(x,y+1); 
    }
}

int main(){
    freopen("expansion.in","r",stdin);
    freopen("expansion.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++)scanf("%d",&a[i]);
    for(int i=1;i<=m;i++)scanf("%d",&b[i]);
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            mapp[i][j]=a[i]+b[j];
//            cout<<mapp[i][j]<<" ";
        }
//        cout<<endl;
    }
    for(int i=1;i<=n;i++){
        dfs(i,1);
        memset(used,0,sizeof(used));
    }
    printf("%d",res);
    return 0;
}