class Solution:
# @param A : integer
# @param B : integer
# @return an integer
def solve(self, N, S):
dp = [[ 0 for i in range(S+1)] for j in range(N+1)]
i=2
j=1
while(j<=S and j<=9):
dp[1][j]=1
j+=1
while(i<=N):
j=1
while(j<=S):
dp[i][j]=(dp[i-1][j]+dp[i][j-1])%1000000007
if j>9:
dp[i][j]-=dp[i][j-10]
dp[i][j]=dp[i][j]%1000000007
j+=1
i+=1
return dp[N][S]%1000000007