/* package whatever; // don't place package name! */
import java.util.*;
import java.lang.*;
import java.io.*;
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
{
// your code goes here
Scanner sc
=new Scanner
(System.
in); // no of ones
int n=sc.nextInt();
// no of zeros
int m=sc.nextInt();
int dp[][]=new int[n+m+1][n+1];
dp[0][0]=0;
dp[1][0]=1;
dp[1][1]=1;
for(int i=2;i<=n+m;i++)
{
for(int j=0;j<=n;j++)
{
if(j>0)
dp[i][j]+=dp[i-1][j]+dp[i-1][j-1];
else
dp[i][j]+=dp[i-1][j];
}
}
System.
out.
println(dp
[n
+m
][n
]); }
}
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