#include <fstream>
#include <cmath>
#include <vector>
#include <iomanip>
#include <queue>
#include <cstring>
#include <algorithm>
#include <queue>
#include <unordered_set>
#include <set>
#include <map>
using namespace std;

const int MAXN = 256;
const int MOD = 9901;

int v[2 * MAXN];
int dp[2 * MAXN][2 * MAXN];

int main() {
    ifstream cin("culori.in");
    ofstream cout("culori.out");
    int n;
    cin >> n;
    n = 2 * n - 1;
    for (int i = 1; i <= n; i++) {
        cin >> v[i];
        dp[i][i] = 1;
    }
    for (int l = 3; l <= n; l += 2)
        for (int i = 1; i + l - 1 <= n; i++) {
            int j = i + l - 1;
            if (v[i] == v[j])
                for (int k = i + 1; k < j; k++)
                    dp[i][j] = (dp[i][j] + dp[i + 1][k] * dp[k + 1][j]) % MOD;
        }
    cout << dp[1][n];
    return 0;
}