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OI-codes/NFLSOJ/13368/13368.cpp

39 lines
759 B
C++

#include <iostream>
#include <fstream>
// using std::cin;
// using std::cout;
std::ifstream cin("string.in");
std::ofstream cout("string.out");
const char endl = '\n';
const int N = 1e6 + 5;
const int mod = 998244353;
int a, b, inv[N << 2], ans;
int main() {
std::ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> a >> b;
inv[0] = inv[1] = 1;
for (int i = 2; i <= a + a + b; i++) {
inv[i] = static_cast<long long>(mod - mod / i) * inv[mod % i] % mod;
}
for (int i = 1; i <= a; i++) {
ans = (static_cast<long long>(ans) + inv[2 * i - 1]) % mod;
}
for (int i = 1; i <= b; i++) {
ans = (static_cast<long long>(ans) + inv[2 * a + i]) % mod;
}
cout << ans << endl;
return 0;
}