#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

const int N = , P = 1e9 + ;

int n, k;

ll ans;

ll a[N], b[N], inv[N], facinv[N], fac[N], dp[N][N], g[N];

ll C(int n, int m)

{

    return fac[n] * facinv[m] % P * facinv[n - m] % P;

}

int main()

{

    scanf("%d%d", &n, &k);

    for(int i = ; i <= n; ++i) scanf("%d", &a[i]);

    for(int i = ; i <= n; ++i) scanf("%d", &b[i]);

    if((n + k) & )

    {

        puts("");

        return ;

    }

    k += (n - k) >> ;

    sort(a + , a + n + );

    sort(b + , b + n + );

    inv[] = ; fac[] = facinv[] = ;

    for(int i = ; i <= n; ++i)

    {

        if(i != ) inv[i] = (P - P / i) * inv[P % i] % P;

        facinv[i] = facinv[i - ] * inv[i] % P;

        fac[i] = fac[i - ] * i % P;

    }

    for(int i = , j = ; i <= n; ++i)

    {

        while(a[i] > b[j + ] && j +  <= n) ++j;

        g[i] = j;

    }

    for(int i = ; i <= n; ++i) dp[i][] = ;

    for(int i = ; i <= n; ++i)

        for(int j = ; j <= g[i]; ++j)

            dp[i][j] = (dp[i - ][j] + dp[i - ][j - ] * (g[i] - j + ) % P) % P;

    for(int i = k; i <= n; ++i) ans = ((ans + (((i - k) & ) ? - : ) * dp[n][i] * fac[n - i] % P * C(i, k) % P) % P + P) % P;

    printf("%lld\n", ans);

    return ;

}