13 lines
306 B
Python
13 lines
306 B
Python
import sys
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input=sys.stdin.readline
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MOD=10**9+7
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n,m=map(int,input().split())
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dp=[[0]*(m+1) for _ in range(n+1)]
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dp[1][1]=1
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for i in range(1,n+1):
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for j in range(1,m+1):
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if i==1 and j==1:
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continue
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dp[i][j]=(dp[i-1][j]+dp[i][j-1]+dp[i-1][j-1])%MOD
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print(dp[n][m])
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