const MOD: usize = 1e9 as usize + 7;

fn main() {
    let mut pk = String::new();
    std::io::stdin().read_line(&mut pk).ok();
    let pk: Vec<usize> = pk.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let p = pk[0];
    let k = pk[1];

    let mut dp = vec![vec![0usize; 2]; k+1];
    dp[0][0] = 1;
    for i in 0..k {
        dp[i+1][0] += dp[i][0];
        dp[i+1][0] += dp[i][1];
        dp[i+1][0] += dp[i][0] * p % MOD;
        dp[i+1][0] += dp[i][1];
        dp[i+1][0] %= MOD;
        dp[i+1][1] += dp[i][0] * (p-1) % MOD;
        dp[i+1][1] += dp[i][1] * (p-1) % MOD;
        dp[i+1][1] += dp[i][1] * (p-1) % MOD;
        dp[i+1][1] %= MOD;
    }
    println!("{}", dp[k][0]);
}