pub fn readln() -> String {
    let mut line = String::new();
    ::std::io::stdin()
        .read_line(&mut line)
        .unwrap_or_else(|e| panic!("{}", e));
    line
}
macro_rules !read {($($t :tt ) ,*;$n :expr ) =>{{let stdin =::std ::io ::stdin () ;let ret =::std ::io ::BufRead ::lines (stdin .lock () ) .take ($n ) .map (|line |{let line =line .unwrap () ;let mut it =line .split_whitespace () ;_read !(it ;$($t ) ,*) } ) .collect ::<Vec <_ >>() ;ret } } ;($($t :tt ) ,*) =>{{let line =readln () ;let mut it =line .split_whitespace () ;_read !(it ;$($t ) ,*) } } ;}
macro_rules !_read {($it :ident ;[char ] ) =>{_read !($it ;String ) .chars () .collect ::<Vec <_ >>() } ;($it :ident ;[u8 ] ) =>{Vec ::from (_read !($it ;String ) .into_bytes () ) } ;($it :ident ;usize1 ) =>{$it .next () .unwrap_or_else (||panic !("input mismatch" ) ) .parse ::<usize >() .unwrap_or_else (|e |panic !("{}" ,e ) ) -1 } ;($it :ident ;[usize1 ] ) =>{$it .map (|s |s .parse ::<usize >() .unwrap_or_else (|e |panic !("{}" ,e ) ) -1 ) .collect ::<Vec <_ >>() } ;($it :ident ;[$t :ty ] ) =>{$it .map (|s |s .parse ::<$t >() .unwrap_or_else (|e |panic !("{}" ,e ) ) ) .collect ::<Vec <_ >>() } ;($it :ident ;$t :ty ) =>{$it .next () .unwrap_or_else (||panic !("input mismatch" ) ) .parse ::<$t >() .unwrap_or_else (|e |panic !("{}" ,e ) ) } ;($it :ident ;$($t :tt ) ,+) =>{($(_read !($it ;$t ) ) ,*) } ;}

fn mpow(n: i64, m: i64) -> i64 {
    if n == 0 {
        1
    } else {
        let mut a = mpow(n >> 1, m);
        a *= a;
        if n & 1 == 1 {
            a <<= 1;
        }
        a % m
    }
}

const M: i64 = 998244353;
fn main() {
    let t = read!(usize);
    let mut ans = Vec::with_capacity(t);
    for _ in 0..t {
        let (n, k) = read!(i64, i64);
        let mut x = mpow(n * k, M) - mpow(n * k - k, M);
        if x < M {
            x += M;
        }
        ans.push((x * n) % M);
    }
    for a in ans {
        println!("{}", a);
    }
}