#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include<algorithm>

 using namespace std;

 long long n,m,t[],f[][],ans = 0x3f3f3f3f3f,mi;

 int main() {

     scanf("%lld%lld",&n,&m);

     for(int i = ;i <= n; i++)

         scanf("%lld",&t[i]),mi = mi < t[i] ? mi : t[i];

     for(int i = ;i <= n; i++) t[i] -= mi;

     sort(t+,t+n+);

     memset(f,0x3f,sizeof(f));

     for(int i = ;i <  * m; i++) f[][i] = i;

     for(int i = ;i < n; i++)

         for(int j = ;j <  * m; j++) {

             if(f[i][j] < 0x3f3f3f3f3f3f3f3f) {

                 if(t[i] + j >= t[i+])

                     f[i+][t[i]+j-t[i+]] = min(f[i+][t[i]+j-t[i+]],f[i][j]+j+t[i]-t[i+]);

                 for(int k = t[i] + j + m >= t[i+] ?  : t[i+] - t[i] - j - m;t[i] + j + m + k - t[i+] <  * m; k++)

                     if(t[i] + j + k + m >= t[i+])

                         f[i+][t[i]+j+k+m-t[i+]] = min(f[i+][t[i]+j+k+m-t[i+]],f[i][j]+t[i]+j+m+k-t[i+]);

                 if(t[i] + j + m < t[i+])

                     for(int k = ;k < m * ; k++)

                         f[i+][k] = min(f[i+][k],f[i][j] + k);

             }

         }

     for(int i = ;i < m * ; i++)

         ans = min(ans,f[n][i]);

     printf("%lld",ans);

     return ;

 }