const MOD: u64 = 1_000_000_007;

fn main() {
    let ref mut buf = String::new();
    std::io::Read::read_to_string(&mut std::io::stdin(), buf).ok();
    let mut iter = buf.split_whitespace();

    macro_rules! scan {
        ([$t:tt; $n:expr]) => ((0..$n).map(|_| scan!($t)).collect::<Vec<_>>());
        (($($t:tt),*)) => (($(scan!($t)),*));
        (Usize1) => (scan!(usize) - 1);
        (Bytes) => (scan!(String).into_bytes());
        ($t:ty) => (iter.next().unwrap().parse::<$t>().unwrap());
    }

    let (n, k) = scan!((u64, u64));

    let pow = |mut a: u64, mut n: u64| {
        let mut res = 1;
        while n > 0 {
            if n & 1 == 1 {
                res = res * a % MOD;
            }
            a = a * a % MOD;
            n >>= 1;
        }
        res
    };

    let ans = (pow(n, k) + MOD - pow(n - 1, k)) % MOD * n % MOD;
    println!("{}", ans);
}