def cmb(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    return g1[n] * g2[r] * g2[n-r] % mod

mod = 10**9+7 #出力の制限
N = 10**6
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル

for i in range( 2, N + 1 ):
    g1.append( ( g1[-1] * i ) % mod )
    inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
    g2.append( (g2[-1] * inverse[-1]) % mod )

N, K = map(int, input().split())
MOD = 10**9+7
n = min(N,K)
ans = 0
for i in range(max(1,N-n),N+1):
  m = cmb(N,i,MOD)
  m *= cmb(N-1,i-1, MOD)
  ans += m
  ans %= MOD
print(ans) def cmb(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    return g1[n] * g2[r] * g2[n-r] % mod cmb if ( r<0 or r>n ):
        return 0
     r<0 or r>n r<0 r 0 r>n r n return 0 0 r = min(r, n-r) r min(r, n-r) min r n-r n r return g1[n] * g2[r] * g2[n-r] % mod g1[n] * g2[r] * g2[n-r] % mod g1[n] * g2[r] * g2[n-r] g1[n] * g2[r] g1[n] g1 n g2[r] g2 r g2[n-r] g2 n-r n r mod n n r r mod mod mod = 10**9+7 mod 10**9+7 10**9 10 9 7 N = 10**6 N 10**6 10 6 g1 = [1, 1] g1 [1, 1] 1 1 g2 = [1, 1] g2 [1, 1] 1 1 inverse = [0, 1] inverse [0, 1] 0 1 for i in range( 2, N + 1 ):
    g1.append( ( g1[-1] * i ) % mod )
    inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
    g2.append( (g2[-1] * inverse[-1]) % mod ) i range( 2, N + 1 ) range 2 N + 1 N 1 g1.append( ( g1[-1] * i ) % mod ) g1.append g1 append ( g1[-1] * i ) % mod g1[-1] * i g1[-1] g1 -1 i mod inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod ) inverse.append inverse append ( -inverse[mod % i] * (mod//i) ) % mod -inverse[mod % i] * (mod//i) -inverse[mod % i] inverse[mod % i] inverse mod % i mod i mod//i mod i mod g2.append( (g2[-1] * inverse[-1]) % mod ) g2.append g2 append (g2[-1] * inverse[-1]) % mod g2[-1] * inverse[-1] g2[-1] g2 -1 inverse[-1] inverse -1 mod N, K = map(int, input().split()) N map(int, input().split()) map int input().split() ().split () input split K MOD = 10**9+7 MOD 10**9+7 10**9 10 9 7 n = min(N,K) n min(N,K) min N K ans = 0 ans 0 for i in range(max(1,N-n),N+1):
  m = cmb(N,i,MOD)
  m *= cmb(N-1,i-1, MOD)
  ans += m
  ans %= MOD i range(max(1,N-n),N+1) range max(1,N-n) max 1 N-n N n N+1 N 1 m = cmb(N,i,MOD) m cmb(N,i,MOD) cmb N i MOD m *= cmb(N-1,i-1, MOD) m cmb(N-1,i-1, MOD) cmb N-1 N 1 i-1 i 1 MOD ans += m ans m ans %= MOD ans MOD print(ans) print ans g1 = [1, 1] [1, 1] g1 N = 10**6 10**6 N def cmb(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    return g1[n] * g2[r] * g2[n-r] % mod def cmb(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    return g1[n] * g2[r] * g2[n-r] % mod cmb K = map(int, input().split()) map(int, input().split()) K m *= cmb(N-1,i-1, MOD) cmb(N-1,i-1, MOD) m ans %= MOD MOD ans m = cmb(N,i,MOD) cmb(N,i,MOD) m MOD = 10**9+7 10**9+7 MOD inverse = [0, 1] [0, 1] inverse N, K = map(int, input().split()) map(int, input().split()) N ans += m m ans ans = 0 0 ans n = min(N,K) min(N,K) n mod = 10**9+7 10**9+7 mod g2 = [1, 1] [1, 1] g2
def cmb(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    return g1[n] * g2[r] * g2[n-r] % mod

mod = 10**9+7 #出力の制限
N = 10**6
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル

for i in range( 2, N + 1 ):
    g1.append( ( g1[-1] * i ) % mod )
    inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
    g2.append( (g2[-1] * inverse[-1]) % mod )

N, K = map(int, input().split())
MOD = 10**9+7
n = min(N,K)
ans = 0
for i in range(max(1,N-n),N+1):
  m = cmb(N,i,MOD)
  m *= cmb(N-1,i-1, MOD)
  ans += m
  ans %= MOD
print(ans)