#include <stdio.h>

int main () {
  int t = 0;
  long long n = 0LL;
  long long x = 0LL;
  
  int res = 0;
  
  long long mod_num = 998244353LL;
  
  res = scanf("%d", &t);
  
  while (t > 0) {
    res = scanf("%lld", &n);
    res = scanf("%lld", &x);
    if (x%2LL == 1LL) {
      printf("%lld\n", ((n+1LL)/2LL)%mod_num);
    } else {
      long long ans = (n/(2LL*x+1LL))*(x+1LL);
      if (n%(2LL*x+1LL) < x) {
        ans += (n%(2LL*x+1LL)+1LL)/2LL;
      } else {
        ans += 1LL+(n%(2LL*x+1LL)-x)/2LL;
        ans += x/2LL;
      }
      printf("%lld\n", ans%mod_num);
    }
    t--;
  }
  
  return 0;
}