#include <iostream> #include <string> #include <vector> #include <algorithm> #include <atcoder/modint> using namespace std; using i32 = int32_t; using u32 = uint32_t; using i64 = int64_t; using u64 = uint64_t; #define rep(i,n) for(int i=0; i<(int)(n); i++) const i64 INF = 1001001001001001001; using modint = atcoder::static_modint<998244353>; int main(){ i64 N, M; cin >> N >> M; modint factN = 1; for(int i=1; i<=2*N; i++) factN *= i; modint comb = factN.inv(); for(int i=M+1; i<=M+2*N; i++) comb *= i; modint ans = comb * M * N / (2*N+1); cout << ans.val() << '\n'; return 0; } struct ios_do_not_sync{ ios_do_not_sync(){ std::ios::sync_with_stdio(false); std::cin.tie(nullptr); } } ios_do_not_sync_instance;