#include<stdio.h>
#define nmax 260
#define modulo 9901
int n, i, ne, p1, p2, lg, k, v[nmax];
int nr[2*nmax][2*nmax];

int main()
{
    freopen("culori.in","r",stdin);
    freopen("culori.out","w",stdout);
    scanf("%ld",&n);    ne=2*n-1;
    for (i=1;i<=ne;i++)
    {
        scanf("%ld",&v[i]);
        nr[i][i]=1;
    }
    for (lg=3;lg<=ne;lg+=2)
        for (p1=1;p1+lg-1<=ne;p1++)
        {
            p2=p1+lg-1;
            if (v[p1]==v[p2])
                for (k=p1+2;k<=p2;k++)
                    nr[p1][p2]=(nr[p1][p2] + nr[p1+1][k-1]*nr[k][p2])%modulo;
        }
    printf("%ld",nr[1][ne]);

    return 0;
}