class HelloWorld {
// 根据推理可得
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int n1 = in.nextInt();
int n2 = in.nextInt();
int[][] ss = new int[n1+1][n2+1];
for (int i = 1; i <= n1; i++) {
for (int j = 1; j <= n2; j++) {
if (i == 1) {
ss[i][j] = j + 1;
} else if (j == 1) {
ss[i][j] = i + 1;
} else {
ss[i][j] = ss[i][j-1]+ss[i-1][j];
}
}
}
System.out.println(ss[n1][n2]);
}
}