#include<cstdio>
#include<algorithm>
#define mod 1000000007
#define maxn 105
using namespace std;
int n,a[maxn],f[maxn/2][maxn][maxn];
int main()
{
	scanf("%d",&n);
	for(int i=1;i<2*n;i++) scanf("%d",&a[i]);
	sort(a+1,a+2*n);
	f[n][1][0]=1;
	for(int i=n-1;i;i--)
	{
		int al=(a[i]!=a[i+1]),ar=(a[2*n-i]!=a[2*n-i-1]);
		for(int l=0;l<2*n;l++)
			for(int r=0;r+l<2*n;r++)
				if(f[i+1][l][r])
				{
					for(int dl=1;dl<=l+al;dl++) f[i][l+al-dl+1][r+ar+(dl>1)]=(f[i][l+al-dl+1][r+ar+(dl>1)]+f[i+1][l][r])%mod;
					for(int dr=1;dr<=r+ar;dr++) f[i][l+al+1][r+ar-dr]=(f[i][l+al+1][r+ar-dr]+f[i+1][l][r])%mod;
				}
	}
	int ans=0;
	for(int i=0;i<n*2;i++)
		for(int j=0;j<n*2;j++) ans=(ans+f[1][i][j])%mod;
	printf("%d\n",ans);
}