#include <iostream> #include <vector> using namespace std; int main() { int m, n; cin >> m >> n; vector<vector<int>> dp(m, vector<int>(n, 0)); // 第一行和第一列初始化 for (int i = 0; i < m; i++) dp[i][0] = 1; for (int j = 0; j < n; j++) dp[0][j] = 1; // 递推 for (int i = 1; i < m; i++) { for (int j = 1; j < n; j++) { dp[i][j] = dp[i-1][j] + dp[i][j-1]; } } cout << dp[m-1][n-1] << endl; return 0; }