1 #include <iostream> 2 #include <cstdio> 3 #include <algorithm> 4 #include <cstring> 5 #include <string> 6 using namespace std; 7 typedef long long ll; 8 const int maxn = 2000+10; 9 const int mod = 998244353; 10 const int inf = 0x3f3f3f3f; 11 #define rep(i,first,second) for(ll i=first;i<=second;i++) 12 #define dep(i,first,second) for(ll i=first;i>=second;i--) 13 #define erep(i,u) for(ll i=head[u];~i;i=e[i].nxt) 14 #define lowbit(i) i&(-i) 15 16 int a[maxn][maxn]; 17 void init(){ 18 rep(i,1,2000){ 19 a[i][0]=a[i][i]=1; 20 rep(j,1,i-1){ 21 a[i][j]=(a[i-1][j]+a[i-1][j-1])%mod; 22 } 23 } 24 } 25 int main() 26 { 27 init(); 28 int n,m; 29 while(~scanf("%d%d",&n,&m)){ 30 printf("%d ",a[n][m]); 31 } 32 return 0; 33 }