using System; using static System.Console; using System.Linq; using System.Collections.Generic; class Program { public static void Main() { Solve(); } static void Solve() { var n = long.Parse(ReadLine()); var m = int.Parse(ReadLine()); var mod = 998_244_353; var ncr = new NCR(m, mod); var res = ncr.Exp(2, n); var tmp = 1L; for (var i = 0; i < m; ++i) { res = (res - tmp * ncr.RevFact(i) % mod + mod) % mod; tmp = tmp * (n - i) % mod; } WriteLine(res); } class NCR { int[] facts; int[] revFacts; int mod; public NCR(int n, int mod) { facts = new int[n + 1]; revFacts = new int[n + 1]; this.mod = mod; facts[0] = 1; var tmp = 1L; for (var i = 1; i <= n; ++i) { tmp = (tmp * i) % mod; facts[i] = (int)tmp; } tmp = Exp(facts[n], mod - 2); revFacts[n] = (int)tmp; for (var i = n; i > 1; --i) { tmp = (tmp * i) % mod; revFacts[i - 1] = (int)tmp; } revFacts[0] = 1; } public long Exp(long n, long k) { n = n % mod; if (k == 0) return 1; if (k == 1) return n; var half = Exp(n, k / 2); var result = (half * half) % mod; return ((k % 2) == 0) ? result : ((result * n) % mod); } public long Calc(int n, int r) { return (long)facts[n] * revFacts[r] % mod * revFacts[n - r] % mod; } public long Calc2(long n, int r) { var tmp = 1L; for (var i = 0; i < r; ++i) { tmp = tmp * (n - i) % mod; } return tmp * revFacts[r] % mod; } public long NPR(int n, int r) { return (long)facts[n] * revFacts[r] % mod; } public long Fact(int n) { return facts[n]; } public long RevFact(int n) { return revFacts[n]; } } }