#include <bits/stdc++.h>

    using namespace std;

    typedef long long ll;

    int n, m;
    ll ans = 0;
    ll f[350][350][350];
    ll a[200005];
    ll b[200005];

    int main()
    {
        freopen("expansion.in", "r", stdin);
        freopen("expansion.out", "w", stdout);

        ios::sync_with_stdio(false);
        cin.tie(0); cout.tie(0);

        cin >> n >> m;
        for(int i = 1; i <= n; ++i)
            cin >> a[i];
        for(int i = 1; i <= m; ++i)
            cin >> b[i];

        for(int i = 1; i <= n; ++i)
            if(a[i]+b[m] >= 0)
            f[i][m][i] = 1;

        for(int i = m; i > 0; --i)
            for(int j = n; j > 0; --j)
            {
                if(a[j]+b[i] >= 0)
                {
                    for(int k = 1; k <= n; ++k)
                    {
                        if(f[j][i+1][k] > 0)
                            f[j][i][k] = 1;
                        if(f[j+1][i][k] > 0)
                            f[j][i][k] = 1;
                    }
                }
            }

        for(int i = 1; i <= n; ++i)
            for(int j = 1; j <= n; ++j)
                    ans += f[i][1][j];

        cout << ans;

       	return 0;
    }