//https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 より
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

//

fn run() {
    input! {
        n: usize,
        v: usize,
        c: [usize; n],
    }
    let mut c = c;
    for i in 1..n {
        c[i] += c[i - 1];
    }
    if v < n {
        println!("{}", c[n - 1]);
        return;
    }
    let v = v - n;
    let w = n * n;
    let mut dp = vec![std::usize::MAX / 2; w + 1];
    dp[0] = 0;
    for (i, c) in c.iter().enumerate() {
        let a = i + 1;
        for j in a..=w {
            dp[j] = std::cmp::min(dp[j], dp[j - a] + *c);
        }
    }
    let mut max = (1, std::usize::MAX / 2);
    for (i, c) in c.iter().enumerate() {
        if max.1 * (i + 1) > *c * max.0 {
            max = (i + 1, *c);
        }
    }
    let mut ans = std::usize::MAX / 2;
    for (i, &a) in dp.iter().enumerate().take(v + 1) {
        let rem = v - i;
        if rem % max.0 == 0 {
            ans = std::cmp::min(ans, a + (rem / max.0) * max.1);
        }
    }
    ans += c[n - 1];
    println!("{}", ans);
}

fn main() {
    run();
}