#include<bits/stdc++.h>
using namespace std;
#define fo(v,a,b) for(int v = a; v <= b; v++)
#define fr(v,a,b) for(int v = a; v >= b; v--)
#define cl(a,v) memset(a, v, sizeof(a))

typedef long long ll;

const int INF = 1e9 + 7;
const int N = 1e6 + 10;

int n, m, A[N], B[N], mx, mn;
int st[N], top, pos[N], gap[N], cnt;

priority_queue<pair<int, int>, vector<pair<int, int> >,
    greater<pair<int, int> > > Q;

void Solve(bool fl, int *arr) {
    top = cnt = 0, cl(st, 0), cl(pos, 0), cl(gap, 0);
    while(Q.size()) Q.pop();

    mx = -INF, mn = INF;
    fo(i, 1, m) mx = max(mx, B[i]), mn = min(mn, B[i]);

    fo(i, 1, m) if(top == 0 || B[i] > B[st[top]])
        st[++top] = i;
    pos[cnt = 1] = 1, gap[1] = B[1];
    fo(i, 2, top) {
        int z = INF;
        fo(j, st[i - 1] + 1, st[i]) z = min(z, B[j]);
        if(gap[i - 1] <= z) pos[cnt] = st[i];
        else pos[++cnt] = st[i], gap[cnt] = z;
    }

    fo(i, 1, n) {
        if(A[i] + mx < 0) {
            while(Q.size()) Q.pop();
            continue;
        }
        if(A[i] + B[1] < 0) {
            int l = 1, r = cnt, mid;
            while(l < r) {
                mid = (l + r) >> 1;
                if(A[i] + B[pos[mid]] < 0) l = mid + 1;
                else r = mid;
            }
            while(Q.size() && Q.top().first < l) Q.pop();
        } else {
            Q.push(make_pair(1, 1));
            int l = 1, r = cnt, mid;
            while(l < r) {
                mid = (l + r + 1) >> 1;
                if(A[i] + gap[mid] >= 0) l = mid;
                else r = mid - 1;
            }
            int cur = 0;
            while(Q.size() && Q.top().first <= l)
                cur += Q.top().second, Q.pop();
            if(cur) Q.push(make_pair(l, cur));
        }
        if(A[i] + mn >= 0) {
            assert(Q.top().first == cnt);
            arr[i] = Q.top().second;
            if(fl) while(Q.size()) Q.pop();
        }
    }
}

int preCnt[N], sufCnt[N]; ll ans;

int main()
{
    // freopen("travel6.in", "r", stdin);

    scanf("%d%d", &n, &m);
    fo(i, 1, n) scanf("%d", &A[i]);
    fo(i, 1, m) scanf("%d", &B[i]);

    Solve(false, preCnt);
    reverse(A + 1, A + n + 1), reverse(B + 1, B + m + 1);
    Solve(true, sufCnt);

    fo(i, 1, n) ans += (ll)preCnt[i] * sufCnt[n - i + 1];
    printf("%lld\n", ans);

    return 0;
}
/*
 
*/