#include <cstdio>
#include <cstring>
#include <algorithm>
#define P 998244353

using namespace std;

typedef long long ll;

ll powmod(ll x, ll y = P - 2, ll p = P) {
    ll ans = 1;
    while(y) {
        if(y & 1) ans = ans * x % p;
        x = x * x % p;
        y >>= 1;
    }
    return ans;
}

ll Fac[1000010], Rev[1000010], n, m;

ll C(ll x, ll y) {
    if(x < 0 || y < 0 || x < y) return 0;
    return Fac[x] * Rev[y] % P * Rev[x - y] % P;
}

int main() {
    for(int i = 0; i <= 1000001; i++) Fac[i] = !i ? 1 : Fac[i - 1] * i % P;
    for(int i = 1000001; i >= 0; i--) Rev[i] = i == 1000001 ? powmod(Fac[i]) : Rev[i + 1] * (i + 1) % P;
    scanf("%lld%lld", &n, &m);
    ll f = C(n + m, m), g = f, ans = f;
    for(int i = 1; i < n + m; i++) {
        g = (g + (i % 2 == 1 ? -2 : 1) * C(i - 1, (i / 2)) * (C(n + m - (i % 2 == 1) - i, m - i + (i / 2)))) % P;
        ans = (ans + (f = (f + g) % P) * Rev[i + 1] % P * Fac[i]) % P;
    }
    printf("%lld\n", ((ans * powmod(C(n + m, m))) % P + P) % P);
    return 0;
}
