#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef int _loop_int;
#define REP(i,n) for(_loop_int i=0;i<(_loop_int)(n);++i)
#define FOR(i,a,b) for(_loop_int i=(_loop_int)(a);i<(_loop_int)(b);++i)
#define FORR(i,a,b) for(_loop_int i=(_loop_int)(b)-1;i>=(_loop_int)(a);--i)

#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define DEBUG_VEC(v) cout<<#v<<":";REP(i,v.size())cout<<" "<<v[i];cout<<endl
#define ALL(a) (a).begin(),(a).end()

#define CHMIN(a,b) a=min((a),(b))
#define CHMAX(a,b) a=max((a),(b))

// mod
const ll MOD = 1000000007ll;
#define FIX(a) ((a)%MOD+MOD)%MOD

// floating
typedef double Real;
const Real EPS = 1e-11;
#define EQ0(x) (abs(x)<EPS)
#define EQ(a,b) (abs(a-b)<EPS)
typedef complex<Real> P;

int n,k;
int a[353];
ll dp[353][52525];

int main(){
  if(false){
    FOR(n,1,6){
      int mx = n*(n-1)/2;
      vi cnt(mx+1, 0);
      vi v(n);
      REP(i,n)v[i]=i;
      do{
        int tmp = 0;
        REP(i,n)REP(j,i)if(v[j]>v[i])tmp++;
        cnt[tmp]++;
      }while(next_permutation(ALL(v)));
      REP(i,mx)cnt[i+1]+=cnt[i];
      REP(i,mx+1)printf("%d,",cnt[i]);
    }
  }
  // A161169
  // T(n,k) = T(n,k-1) + T(n-1,k) - T(n-1,k-n), taking T(n,k)=0 for k<0.
  scanf("%d%d",&n,&k);
  REP(i,n)scanf("%d",a+i);
  dp[0][0] = 1;
  REP(i,n+1)REP(j,i*(i-1)/2+1){
    if(j==0){
      dp[i][j] = 1ll;
      continue;
    }
    ll tmp = dp[i][j-1] + dp[i-1][min(j, (i-1)*(i-2)/2)];
    if(j-i>=0)tmp += MOD - dp[i-1][min(j-i, (i-1)*(i-2)/2)];
    dp[i][j] = tmp%MOD;
  }
  printf("%lld\n",dp[n][k]);
  return 0;
}