#include <stdio.h>

const int Mod = 998244353;
long long memo[4001][4001] = {{1}};
int sum_memo[4001][4001] = {};

long long recursion(int x, int y)
{
	if (memo[x][y] != 0) return memo[x][y];
	if (x > 0) memo[x][y] += recursion(x - 1, y);
	if (y > 0) memo[x][y] += recursion(x, y - 1);
	if (x > 0 && y > 0) memo[x][y] += recursion(x - 1, y - 1) * 2;
	memo[x][y] %= Mod;
	return memo[x][y];
}

int sum_recursion(int x, int y)
{
	if (sum_memo[x][y] != 0) return sum_memo[x][y];
	else sum_memo[x][y] = recursion(x, y);
	if (x > 0 && y > 0) sum_memo[x][y] += sum_recursion(x - 1, y - 1);
	if (sum_memo[x][y] >= Mod) sum_memo[x][y] -= Mod;
	return sum_memo[x][y];
}

int main()
{
	int i, Q, x, y;
	scanf("%d", &Q);
	for (i = 1; i <= Q; i++) {
		scanf("%d %d", &x, &y);
		printf("%d\n", sum_recursion(x, y));
	}
	fflush(stdout);
	return 0;
}