k,l=map(int,input().split())
list1=[[0]*105 for i in range(105)]
for i in range(105):
list1[1][i]=1#初始化第一行，我们是从最后一位开始向前的所以最后一位可以为0
#print(list1[1][i])
for i in range(2,l+1):#从第二位开始
for j in range(k):
for x in range(k):
if (x!=(j+1) and x!=(j-1)):
list1[i][j]+=list1[i-1][x]
list1[i][j]%=1000000007
sum1=0
for i in range(1,k):
sum1+=list1[l][i]
sum1%=1000000007
print(sum1)