// compile: g++ -o data data.cpp -O3 -std=gnu++20 -Wall -Wextra -Wshadow -D_GLIBCXX_ASSERTIONS -ggdb3 -fmax-errors=2 -DLOCAL
// run: ./data < data.in
#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#ifdef LOCAL
#include <debug/codeforces.h>
#define debug(x...) _debug_print(#x, x);
#else
#define debug(x...)
#endif
template<typename...Args> void print_(Args...args){((cout<<args<<" "),...)<<endl;}
#define rep(i,a,b) for(int i=(a);i<(int)(b);++i)
#define sz(v) ((int)(v).size())
#define print(...) print_(__VA_ARGS__);
#define INTMAX (int)(9223372036854775807)
#define INF (int)(1152921504606846976)
#define double long double
#define int long long
#define MAXN 200010

struct node {
    int w, adult;
    bool operator<(const node &other) const {
        return w < other.w;
    }
};

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

    int n; cin >> n;
    string str; cin >> str;
    vector<node> a(n+1);
    rep(i, 1, n+1) cin >> a[i].w, a[i].adult = str[i-1]=='1';
    sort(a.begin()+1, a.end());
    vector<int> s(n+1);
    s[0] = 0;
    rep(i, 1, n+1) s[i] = s[i-1] + a[i].adult;
    // debug(a)
    int ans = n - s[n];
    rep(i, 1, n+1) {
        if (a[i].w == a[i-1].w) continue;
        int c = (i-1) - s[i-1];
        c += s[n] - s[i-1];
        ans = max(ans, c);
    }
    cout << ans << endl;

    return 0;
}