#[macro_use]
mod input_mcr {
    // ref: tanakh <https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8>
    // diff: using Parser
    #[macro_export(local_inner_macros)]
    macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut parser = Parser::from_str($s);
        input_inner!{parser, $($r)*}
    };
    (parser = $parser:ident, $($r:tt)*) => {
        input_inner!{$parser, $($r)*}
    };
    (new_stdin_parser = $parser:ident, $($r:tt)*) => {
        let stdin = std::io::stdin();
        let reader = std::io::BufReader::new(stdin.lock());
        let mut $parser = Parser::new(reader);
        input_inner!{$parser, $($r)*}
    };
    ($($r:tt)*) => {
        input!{new_stdin_parser = parser, $($r)*}
    };
}

    #[macro_export(local_inner_macros)]
    macro_rules! input_inner {
    ($parser:ident) => {};
    ($parser:ident, ) => {};
    ($parser:ident, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($parser, $t);
        input_inner!{$parser $($r)*}
    };
}

    #[macro_export(local_inner_macros)]
    macro_rules! read_value {
    ($parser:ident, ( $($t:tt),* )) => {
        ( $(read_value!($parser, $t)),* )
    };
    ($parser:ident, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($parser, $t)).collect::<Vec<_>>()
    };
    ($parser:ident, chars) => {
        read_value!($parser, String).chars().collect::<Vec<char>>()
    };
    ($parser:ident, char_) => {
        read_value!($parser, String).chars().collect::<Vec<char>>()[0]
    };
    ($parser:ident, usize1) => {
        read_value!($parser, usize) - 1
    };
    ($parser:ident, i64_) => {
        $parser.fast_i64()
    };
    ($parser:ident, usize_) => {
        $parser.fast_i64() as usize
    };
    ($parser:ident, usize1_) => {
        ($parser.fast_i64() - 1) as usize
    };
    ($parser:ident, $t:ty) => {
        $parser.next::<$t>().expect("Parse error")
    };
}

    use std::io;
    use std::io::BufRead;
    use std::str;

    // ref: tatsuya6502 <https://qiita.com/tatsuya6502/items/cd448486f7ef7b5b8c7e>
    // ref: wariuni <https://qiita.com/tatsuya6502/items/cd448486f7ef7b5b8c7e#comment-7040a5ae96305e884eb9>
    // diff: using std::io::BufRead::fill_buf()
    pub struct Parser<R> {
        pub reader: R,
        buf: Vec<u8>,
        pos: usize,
    }

    impl Parser<io::Empty> {
        pub fn from_str(s: &str) -> Parser<io::Empty> {
            Parser {
                reader: io::empty(),
                buf: s.as_bytes().to_vec(),
                pos: 0,
            }
        }
    }

    impl<R: BufRead> Parser<R> {
        pub fn new(reader: R) -> Parser<R> {
            Parser {
                reader: reader,
                buf: vec![],
                pos: 0,
            }
        }
        pub fn update_buf(&mut self) {
            self.buf.clear();
            self.pos = 0;
            loop {
                let (len, complete) = {
                    let buf2 = self.reader.fill_buf().unwrap();
                    self.buf.extend_from_slice(buf2);
                    let len = buf2.len();
                    (len, buf2[len - 1] <= 0x20)
                };
                self.reader.consume(len);
                if complete {
                    break;
                }
            }
        }
        pub fn next<T: str::FromStr>(&mut self) -> Result<T, T::Err> {
            loop {
                let mut begin = self.pos;
                while begin < self.buf.len() && (self.buf[begin] <= 0x20) {
                    begin += 1;
                }
                let mut end = begin;
                while end < self.buf.len() && (self.buf[end] > 0x20) {
                    end += 1;
                }
                if begin != self.buf.len() {
                    self.pos = end;
                    return unsafe { str::from_utf8_unchecked(&self.buf[begin..end]) }.parse::<T>();
                } else {
                    self.update_buf();
                }
            }
        }
        pub fn fast_i64(&mut self) -> i64 {
            loop {
                let mut begin = self.pos;
                while begin < self.buf.len() && (self.buf[begin] <= 0x20) {
                    begin += 1;
                }
                if begin == self.buf.len() {
                    self.update_buf();
                    continue;
                }
                let mut res = 0;
                let (is_positive, mut end) = match self.buf[begin] {
                    b'+' => (true, begin + 1),
                    b'-' => (false, begin + 1),
                    _ => (true, begin),
                };
                while end < self.buf.len() && (self.buf[end] > 0x20) {
                    res = res * 10 + (self.buf[end] as i64 - '0' as i64);
                    end += 1;
                }
                if begin != self.buf.len() {
                    self.pos = end;
                    return if is_positive { res } else { -res };
                } else {
                    self.update_buf();
                }
            }
        }
    }
}

mod modular {
    use std::marker::PhantomData;
    use std::ops::*;

    pub trait ModP {
        fn as_u64() -> u64;
    }

    #[allow(non_camel_case_types)]
    #[derive(Clone, Copy, Debug)]
    pub struct Mod_1_000_000_007();
    impl ModP for Mod_1_000_000_007 {
        fn as_u64() -> u64 {
            1_000_000_007
        }
    }

    #[allow(non_camel_case_types)]
    #[derive(Clone, Copy, Debug)]
    pub struct Mod_998_244_353();
    impl ModP for Mod_998_244_353 {
        fn as_u64() -> u64 {
            998_244_353
        }
    }

    #[derive(Clone, Copy, PartialEq, Debug)]
    pub struct Modular<P: ModP + Copy>(u32, PhantomData<P>);

    impl<P: ModP + Copy> Modular<P> {
        pub fn new(x: u32) -> Modular<P> {
            Modular((x as u64 % P::as_u64()) as u32, PhantomData)
        }
        pub fn pow(self, n: u64) -> Modular<P> {
            if n == 0 {
                return Modular(1, PhantomData);
            }
            let t = self.pow(n / 2);
            if n % 2 == 0 {
                t * t
            } else {
                t * t * self
            }
        }
        pub fn as_u32(self) -> u32 {
            self.0
        }
    }

    impl<P: ModP + Copy> Add for Modular<P> {
        type Output = Self;
        fn add(self, rhs: Self) -> Self::Output {
            let t = (self.0 + rhs.0) as u64;
            let u = if t < P::as_u64() { t } else { t - P::as_u64() };
            Modular(u as u32, PhantomData)
        }
    }

    impl<P: ModP + Copy> AddAssign for Modular<P> {
        fn add_assign(&mut self, rhs: Self) {
            *self = *self + rhs;
        }
    }

    impl<P: ModP + Copy> Sub for Modular<P> {
        type Output = Self;
        fn sub(self, rhs: Self) -> Self::Output {
            let t = if self.0 >= rhs.0 {
                self.0 as u64 - rhs.0 as u64
            } else {
                self.0 as u64 + P::as_u64() - rhs.0 as u64
            };
            assert!(t < P::as_u64());
            Modular(t as u32, PhantomData)
        }
    }

    impl<P: ModP + Copy> SubAssign for Modular<P> {
        fn sub_assign(&mut self, rhs: Self) {
            *self = *self - rhs;
        }
    }

    impl<P: ModP + Copy> Neg for Modular<P> {
        type Output = Modular<P>;
        fn neg(self) -> Modular<P> {
            Modular((P::as_u64() - self.0 as u64) as u32, PhantomData)
        }
    }

    impl<P: ModP + Copy> Mul for Modular<P> {
        type Output = Self;
        fn mul(self, rhs: Self) -> Self::Output {
            Modular(
                ((self.0 as u64 % P::as_u64()) * (rhs.0 as u64 % P::as_u64()) % P::as_u64()) as u32,
                PhantomData,
            )
        }
    }

    impl<P: ModP + Copy> MulAssign for Modular<P> {
        fn mul_assign(&mut self, rhs: Self) {
            *self = *self * rhs;
        }
    }

    impl<P: ModP + Copy> Div for Modular<P> {
        type Output = Self;
        fn div(self, rhs: Self) -> Self::Output {
            if rhs.0 == 0 {
                loop {}
            }
            assert!(rhs.0 != 0);
            self * rhs.pow(P::as_u64() - 2)
        }
    }

    impl<P: ModP + Copy> DivAssign for Modular<P> {
        fn div_assign(&mut self, rhs: Self) {
            *self = *self / rhs;
        }
    }

    pub fn gen_fact_table<P: ModP + Copy>(n: usize) -> Vec<Modular<P>> {
        let mut res = vec![Modular::<P>::new(1); n + 1];
        for i in 0..n {
            res[i + 1] = res[i] * Modular::<P>::new((i + 1) as u32);
        }
        res
    }

    pub fn gen_inv_table<P: ModP + Copy>(n: usize) -> Vec<Modular<P>> {
        let mut res = vec![Modular::<P>::new(0); n + 1];
        res[1] = Modular::<P>::new(1);
        for i in 2..n + 1 {
            res[i] =
                -res[P::as_u64() as usize % i] * Modular::<P>::new((P::as_u64() / i as u64) as u32);
        }
        res
    }

    /*
    #[test]
    fn test_modular_1_000_000_007() {
        type Mod = Modular<Mod_1_000_000_007>;
        assert_eq!(Mod::new(2).pow(1_000_000).as_u32(), 235_042_059)
    }

    #[test]
    fn test_modular_998_244_353() {
        type Mod = Modular<Mod_998_244_353>;
        assert_eq!(Mod::new(2).pow(1_000_000).as_u32(), 421_273_117);
    }
    */
}

mod permutations {
    pub fn permutations<T: Copy>(xs: &Vec<T>) -> Vec<Vec<T>> {
        let mut buf = vec![];
        let mut used = vec![false; xs.len()];
        let mut tmp = vec![];
        permutations_sub(xs, &mut used, &mut buf, &mut tmp, 0);
        buf
    }

    fn permutations_sub<T: Copy>(
        xs: &Vec<T>,
        used: &mut Vec<bool>,
        buf: &mut Vec<Vec<T>>,
        tmp: &mut Vec<T>,
        i: usize,
    ) {
        if i == xs.len() {
            buf.push(tmp.clone());
            return;
        }
        for k in 0..xs.len() {
            if used[k] {
                continue;
            }
            used[k] = true;
            tmp.push(xs[k]);
            permutations_sub(xs, used, buf, tmp, i + 1);
            tmp.pop();
            used[k] = false;
        }
    }
}

use input_mcr::*;
use std::cmp::*;

use modular::*;
use permutations::*;

type Mod = Modular<Mod_1_000_000_007>;

fn g(xs: &Vec<i64>) -> Mod {
    let n = xs.len();
    let mut is = vec![];
    for i in 0..n - 1 {
        is.push(i);
    }
    let perms = permutations(&is);
    let mut res = Mod::new(0);
    let mut count = vec![0; n];
    for perm in &perms {
        // eprintln!("perm = {:?}", perm);
        let mut es = vec![true; n];
        for &p in perm.iter() {
            let mut q = p;
            loop {
                // eprintln!("q = {}, es = {:?}", q, es);
                res += Mod::new(xs[q + 1] as u32) - Mod::new(xs[q] as u32);
                count[q] += 1;
                q += 1;
                if es[q] {
                    break;
                }
            }
            es[p] = false;
        }
    }
    // eprintln!("count = {:?}", count);
    res
}

fn f(xs: &Vec<i64>) -> Mod {
    let n = xs.len();
    let mut base = Mod::new(1);
    for i in 1..n {
        base *= Mod::new(i as u32);
    }
    let mut count = vec![];
    for i in 0..n - 1 {
        count.push(base / Mod::new((i + 1) as u32));
    }
    for i in 1..n - 1 {
        let t = count[i - 1];
        count[i] += t;
    }
    // eprintln!("count = {:?}", count);
    let mut res = Mod::new(0);
    for i in 0..n - 1 {
        res += Mod::new((xs[i + 1] - xs[i]) as u32) * count[i];
    }
    res
}

fn main() {
    input! {
        n: usize,
        xs: [i64; n],
    }
    //let res2 = g(&xs);
    //// eprintln!("res2 = {:?}", res2);
    let res = f(&xs);
    // eprintln!("ress = {:?}", res);
    println!("{}", res.as_u32());
    return;
    /*
    let mut imos = vec![0i64; n];
    for i in 0..n-1 {
        for k in 0..n-1 {
            if i < k {
                imos[i+1] += 1;
                imos[k+1] -= 1;
            }
        }
    }
    // eprintln!("imos = {:?}", imos);
    let mut t = Mod::new(0);
    let mut ys = vec![];
    for i in 0..n-1 {
        ys.push(t);
        if imos[i] > 0 {
            t += Mod::new(imos[i] as u32);
        }
        else {
            t -= Mod::new((-imos[i]) as u32)
        }
    }
    ys.push(t);
    // eprintln!("ys = {:?}", ys);
    let mut base = Mod::new(1);
    for i in 1..n-1+1 {
        base *= Mod::new(i as u32);
    }
    let mut base2 = Mod::new(1);
    for i in 1..n-1 {
        base2 *= Mod::new(i as u32);
    }
    // eprintln!("base  = {:?}", base);
    // let base2 = Mod::new((n-2) as u32);
    // eprintln!("base2 = {:?}", base2);
    let mut res = Mod::new(0);
    for i in 0..n-1 {
        res += (Mod::new(xs[i+1] as u32) - Mod::new(xs[i] as u32)) * (ys[i+1] * base2 + base)
    }
    println!("{}", res.as_u32());
    */
}



Measured memory_bytes: 6396