#include <bits/stdc++.h>

using namespace std;

const int mod = 1e9 + 7;

int dp[55][111][111];
int A[111];
int n, ans;

int main()
{
	int i, j, k, l, x, y, a, b;
	
	scanf("%d", &n);
	
	for(i=1; i<n+n; i++){
		scanf("%d", A + i);
	}
	
	sort(A + 1, A + n + n);
	
	dp[n][1][1] = 1;
	
	for(i=n-1; i>=1; i--){
		a = A[i] != A[i+1];
		b = A[n+n-i] != A[n+n-i-1];
		
		for(j=1; j<=n+n; j++){
			for(k=1; k<=j; k++){
				x = j + a + b;
				y = k + a;
				
				for(l=1;l<y;l++) dp[i][x-y+l+1][l] = (dp[i][x-y+l+1][l] + dp[i+1][j][k]) % mod;
				for(l=y+1;l<=x;l++) dp[i][x+y-l+1][y+1] = (dp[i][x+y-l+1][y+1] + dp[i+1][j][k]) % mod;
				dp[i][x][y] = (dp[i][x][y] + dp[i+1][j][k]) % mod;
			}
		}
	}
	
	for(i=1; i<=n+n; i++){
		for(j=1; j<=i; j++){
			ans = (ans + dp[1][i][j]) % mod;
		}
	}
	
	printf("%d\n", ans);
	
	return 0;
}