/*
 * author :Sadik Hassan(_sad_)
 *
*/
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")
#include "bits/stdc++.h"
using namespace std;
using   ll =          long long;
using   ld =          long double;
#define nl            "\n"
#define pb            push_back
#define fi            first
#define se            second
#define MP            make_pair
#define PI            (acos(-1.0))
#define rep1(i,n)     for(int i=1;i<=n;i++)
#define rep(i,n)      for(int i=0;i<n;i++)
#define urep(i,n)     for(int i=n-1;i>=0;i--)
#define urep1(i,n)    for(int i=n;i>=1;i--)
#define SZ(s)         (int)s.size()
#define all(x)        (x).begin(), (x).end()
#define rall(x)       (x).rbegin(), (x).rend()
#define w(t)          int t;cin>>t;while(t--)
#define _SAD()     	  ios::sync_with_stdio(0),cin.tie(0),cout.tie(0),cout<<fixed<<setprecision(15);

typedef vector<int> vi;
typedef vector<ll> vii;
typedef set<int> si;
typedef set<ll> sii;
/*---------------------------------------------------------------------*/

const int N = (int)2e5+5;
const int MOD =(int)1e9+7;
const ll INF = (ll)1e18+5;
const int M2 = 998244353;
int main()
{
    _SAD()
    int n,k;
    cin>>n>>k;
    ll cnt=0;
    vii a;
    rep(i,n)
    {
        ll x;
        cin>>x;
        if(x<k)
        {
            a.pb(x);
        }
    }
    sort(all(a));
    ll i=0,j=SZ(a)-1;
    while(i<=j)
    {
        ll pp=min(k-a[i],k-a[j]);
        cnt+=pp;
        a[i]+=pp;
        if(i!=j)a[j]+=pp;
        if(a[j]>=k)j--;
        if(a[i]>=k)i++;
    }
    cout<<cnt<<nl;
    return 0;
}