n,k=map(int, input().split())


def cmb(n, r, p):
  if (r < 0) or (n < r):
    return 0
  r = min(r, n - r)
  return fact[n] * factinv[r] * factinv[n-r] % p

p = 10 ** 9 + 7
N = 2*(10 ** 5 ) # N は必要分だけ用意する
fact = [1, 1]  # fact[n] = (n! mod p) 階乗のmod
factinv = [1, 1]  # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1]  # factinv 計算用 

for i in range(2, N + 1):
  fact.append((fact[-1] * i) % p)
  inv.append((-inv[p % i] * (p // i)) % p)
  factinv.append((factinv[-1] * inv[-1]) % p)

#0の数がmin(n-1,k)
MAX=min(n-1,k)

dp=[0]*(MAX+1)
dp[0]=1
ans=1
for i in range(1,MAX+1):
    ans+=cmb(n,i,p)*cmb(n-i+i-1,i,p)
    ans%=p
    #print(ans)

print(ans) n,k=map(int, input().split()) n map(int, input().split()) map int input().split() ().split () input split k def cmb(n, r, p):
  if (r < 0) or (n < r):
    return 0
  r = min(r, n - r)
  return fact[n] * factinv[r] * factinv[n-r] % p cmb if (r < 0) or (n < r):
    return 0
   (r < 0) or (n < r) r < 0 r 0 n < r n r return 0 0 r = min(r, n - r) r min(r, n - r) min r n - r n r return fact[n] * factinv[r] * factinv[n-r] % p fact[n] * factinv[r] * factinv[n-r] % p fact[n] * factinv[r] * factinv[n-r] fact[n] * factinv[r] fact[n] fact n factinv[r] factinv r factinv[n-r] factinv n-r n r p n n r r p p p = 10 ** 9 + 7 p 10 ** 9 + 7 10 ** 9 10 9 7 N = 2*(10 ** 5 ) N 2*(10 ** 5 ) 2 10 ** 5 10 5 fact = [1, 1] fact [1, 1] 1 1 factinv = [1, 1] factinv [1, 1] 1 1 inv = [0, 1] inv [0, 1] 0 1 for i in range(2, N + 1):
  fact.append((fact[-1] * i) % p)
  inv.append((-inv[p % i] * (p // i)) % p)
  factinv.append((factinv[-1] * inv[-1]) % p)

#0の数がmin(n-1,k) i range(2, N + 1) range 2 N + 1 N 1 fact.append((fact[-1] * i) % p) fact.append fact append (fact[-1] * i) % p fact[-1] * i fact[-1] fact -1 i p inv.append((-inv[p % i] * (p // i)) % p) inv.append inv append (-inv[p % i] * (p // i)) % p -inv[p % i] * (p // i) -inv[p % i] inv[p % i] inv p % i p i p // i p i p factinv.append((factinv[-1] * inv[-1]) % p) factinv.append factinv append (factinv[-1] * inv[-1]) % p factinv[-1] * inv[-1] factinv[-1] factinv -1 inv[-1] inv -1 p MAX=min(n-1,k) MAX min(n-1,k) min n-1 n 1 k dp=[0]*(MAX+1) dp [0]*(MAX+1) [0] 0 MAX+1 MAX 1 dp[0]=1 dp[0] dp 0 1 ans=1 ans 1 for i in range(1,MAX+1):
    ans+=cmb(n,i,p)*cmb(n-i+i-1,i,p)
    ans%=p
    #print(ans) i range(1,MAX+1) range 1 MAX+1 MAX 1 ans+=cmb(n,i,p)*cmb(n-i+i-1,i,p) ans cmb(n,i,p)*cmb(n-i+i-1,i,p) cmb(n,i,p) cmb n i p cmb(n-i+i-1,i,p) cmb n-i+i-1 n-i+i n-i n i i 1 i p ans%=p ans p print(ans) print ans N = 2*(10 ** 5 ) 2*(10 ** 5 ) N fact = [1, 1] [1, 1] fact def cmb(n, r, p):
  if (r < 0) or (n < r):
    return 0
  r = min(r, n - r)
  return fact[n] * factinv[r] * factinv[n-r] % p def cmb(n, r, p):
  if (r < 0) or (n < r):
    return 0
  r = min(r, n - r)
  return fact[n] * factinv[r] * factinv[n-r] % p cmb ans+=cmb(n,i,p)*cmb(n-i+i-1,i,p) cmb(n,i,p)*cmb(n-i+i-1,i,p) ans ans%=p p ans n,k=map(int, input().split()) map(int, input().split()) n k=map(int, input().split()) map(int, input().split()) k inv = [0, 1] [0, 1] inv MAX=min(n-1,k) min(n-1,k) MAX factinv = [1, 1] [1, 1] factinv dp=[0]*(MAX+1) [0]*(MAX+1) dp p = 10 ** 9 + 7 10 ** 9 + 7 p ans=1 1 ans
n,k=map(int, input().split())


def cmb(n, r, p):
  if (r < 0) or (n < r):
    return 0
  r = min(r, n - r)
  return fact[n] * factinv[r] * factinv[n-r] % p

p = 10 ** 9 + 7
N = 2*(10 ** 5 ) # N は必要分だけ用意する
fact = [1, 1]  # fact[n] = (n! mod p) 階乗のmod
factinv = [1, 1]  # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1]  # factinv 計算用 

for i in range(2, N + 1):
  fact.append((fact[-1] * i) % p)
  inv.append((-inv[p % i] * (p // i)) % p)
  factinv.append((factinv[-1] * inv[-1]) % p)

#0の数がmin(n-1,k)
MAX=min(n-1,k)

dp=[0]*(MAX+1)
dp[0]=1
ans=1
for i in range(1,MAX+1):
    ans+=cmb(n,i,p)*cmb(n-i+i-1,i,p)
    ans%=p
    #print(ans)

print(ans)
