#include <fstream>
#include <algorithm>
using namespace std;
int r[100000],v[100000];
ifstream cin ("interval1.in");
ofstream cout ("interval1.out");
int main()
{
    int n,m,i,rest,dif;
    cin>>n>>m;
    for(i=0;i<n;i++)
        cin>>v[i];
    sort(v,v+n);
    int minim=1000000000;
    for(i=0;i<n;i++)
    {
        rest=v[i]%m;
        if(r[rest]==0)
            r[rest]=v[i];
        else
        {
            dif=v[i]-r[rest];
            if(dif<minim)
                minim=dif;
                r[rest]=v[i];
        }
    }
    cout<<minim;
return 0;
}