import java.util.*;

public class Main {
    static long[][] dp;
    static long[] sums;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int v = sc.nextInt();
        sums = new long[n];
        sums[0] = sc.nextInt();
        double min = sums[0];
        int minIdx = 0;
        for (int i = 1; i < n; i++) {
            sums[i] = sums[i - 1] + sc.nextInt();
            if (min > sums[i] / (i + 1.0)) {
                min = sums[i] / (i + 1.0);
                minIdx = i;
            }
        }
        long ans = sums[n - 1];
        v -= n;
        if (v > 0) {
            int div = v / (minIdx + 1);
            ans += sums[minIdx] * div;
            v %= (minIdx + 1);
            dp = new long[n][v + 1];
            for (long[] arr : dp) {
                Arrays.fill(arr, Long.MAX_VALUE / 2);
            }
            ans += dfw(n - 1, v);
        }
        System.out.println(ans);
    }
    
    static long dfw(int idx, int value) {
        if (idx < 0) {
            if (value <= 0) {
                return 0;
            } else {
                return Long.MAX_VALUE / 2;
            }
        }
        if (dp[idx][value] == Long.MAX_VALUE / 2) {
            for (int i = 0; i * (idx + 1) <= value; i++) {
                dp[idx][value] = Math.min(dp[idx][value], dfw(idx - 1, value - i * (idx + 1)) + sums[idx] * i);
            }
        }
        return dp[idx][value];
    }
}