#include<bits/stdc++.h> using namespace std; int f[20][20]; int main() { int m, n; cin >> m >> n; for (int j = 1; j <= n; j++) { f[1][j] = 1; } for (int i = 1; i <= m; i++) { f[i][1] = 1; } for (int i = 2; i <= m; i++) { for (int j = 2; j <= n; j++) { f[i][j] = f[i][j - 1] + f[i - 1][j]; } } cout << f[m][n]; return 0; }