#include <bits/stdc++.h>

using namespace std;

const int N = 2e5 + 5;

int a[N], b[N];
vector<int> pos[N];
int usd[N];

signed main() {
    int n, m; scanf("%d%d", &n, &m);
    for (int i = 1; i <= n; ++i) scanf("%d", &a[i]), pos[a[i]].push_back(i);
    for (int i = 1; i <= n; ++i) scanf("%d", &b[i]);
    int res = 0;
    for (int i = 1; i <= n; ++i) {
        vector<int> S;
        for (auto x : pos[i]) {
            if (!b[x]) S.push_back(x);
            else if (!S.empty()) ++res, usd[x] = usd[S.back()] = 1, S.pop_back();
        }
    }
    for (int i = 1, c = 0; i <= n; ++i) if (!usd[i]) {
        if (!b[i]) ++c;
        else if (c) ++res, c -= 2;
    }
    printf("%d\n", res);
    return 0;
}