while(line = readline()) {
    const arr = line.split(' ').map(item => parseInt(item));
    const [n, m] = arr;
  //这里很坑,fill的参数千万不能直接给array,引用类型修改会影响全部元素
    let table = Array(m + 1).fill(0).map(x => Array(n + 1).fill(1));
    for (let i = 1; i <= n; i++) {
        for(let j=1; j<= m; j++) {
            table[j][i] = table[j - 1][i] + table[j][i-1];
        }
    }
    print(table[m][n]);
}