import std.stdio, std.string, std.conv;
import std.range, std.algorithm, std.array, std.typecons, std.container;
import std.math, std.numeric, core.bitop;

enum inf3 = 1_001_001_001;
enum inf6 = 1_001_001_001_001_001_001L;
enum mod = 1_000_000_007L;


void main() {
    int n, x;
    scan(n, x);
    auto a = readln.split.to!(long[]);

    long amin = inf3;
    int s;

    foreach (i ; 0 .. n) {
        if (amin > a[i]) {
            amin = a[i];
            s = i;
        }
    }

    long ans = amin;
    long p = amin;
    int l, ml;

    foreach (i ; 1 .. n) {
        if (a[(s + i) % n] > p + x) {
            l++;
            p += x;
        }
        else {
            s = i;
            p = a[s];
            l = 0;
        }
        ans += a[s];
        ml = max(l, ml);
    }

    ans += 1L * ml * x;

    writeln(ans);
}









void scan(T...)(ref T args) {
    import std.stdio : readln;
    import std.algorithm : splitter;
    import std.conv : to;
    import std.range.primitives;

    auto line = readln().splitter();
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}

void fillAll(R, T)(ref R arr, T value) {
    static if (is(typeof(arr[] = value))) {
        arr[] = value;
    }
    else {
        foreach (ref e; arr) {
            fillAll(e, value);
        }
    }
}
