#include <bits/stdc++.h>

#define el '\n'
#define ll long long
#define ld long double

#define Beevo ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

using namespace std;

const ld pi = acos(-1);
const int N = 100 + 5, INF = 2e9;

int n, m;
ld d[N][N];
ld dp[N][N];
int a[N], s[N];
bool vis[N][N];

ld dist(int i, int j) {
    ld div = 360.0 / m;

    int diff = min(j - i, m - j + i);

    ld angle = div * diff;

    ld len = angle * pi / 180;

    return 2 * sin(len / 2);
}

ld solve(int idx, int st) {
    if (idx >= n)
        return 0;

    ld &ret = dp[idx][st];

    if (vis[idx][st])
        return ret;

    vis[idx][st] = 1;

    ret = INF;

    for (int i = 0; i < m; i++) {
        if (s[i] != a[idx])
            continue;

        ret = min(ret, d[st][i] + solve(idx + 1, i));
    }

    return ret;
}

void testCase() {
    cin >> n;

    for (int i = 0; i < n; i++)
        cin >> a[i];

    cin >> m;

    for (int i = 0; i < m; i++)
        cin >> s[i];

    s[m] = m;

    for (int i = 0; i < m; i++) {
        d[i][i] = 0;

        for (int j = i + 1; j < m; j++)
            d[i][j] = d[j][i] = dist(i, j);
    }

    for (int i = 0; i < m; i++)
        d[i][m] = d[m][i] = 1;

    memset(dp, -1, sizeof dp);

    cout << fixed << setprecision(6) << solve(0, m);
}

signed main() {
    Beevo

    int T = 1;
//    cin >> T;

    while (T--)
        testCase();

    return 0;
}