ДЗ 13 Н 3

x = int(input())
y = int(input())
a = [[0]  * x for i in range (y - 1)] + [[1] * x]
for i in range (y - 1):
    a[i][x - 1] = 1
for i in range(2, y + 1):
    for j in range(2, x + 1):
        a[y - i][x - j] = a[y - i + 1][x - j] + a[y - i][x - j + 1]
print (a[0][0])