#include<iostream>
#include<vector>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<string>
#include<queue>
#include<cmath>
#include<set>
using namespace std;
long long a[123456]; int n,p;
int erf(int l,int r,long long tt)
{
    while(l<r-1)
    {
        int mid=(l+r)/2;
     if(tt+a[mid]<p)
     {
        l=mid;
     }
     else
     {
        r=mid;
      }
    }
    return l;
}
int main()
{

    while(scanf("%d%d",&n,&p)!=EOF)
    {
        for(int i=0;i<n;i++)
        {
            scanf("%I64d",&a[i]);
            a[i]=a[i]%p;
        }
        sort(a,a+n);
        long long maxx=-1;
        for(int i=n-1;i>0;i--)
        {
            long long t=(a[i]+a[i-1])%p;
            long long tt =(a[erf(0,i,a[i])]+a[i])%p;
            if(t>maxx)maxx=t;
            if(tt>maxx)maxx=tt;
        }
        cout<<maxx<<endl;
    }
   return 0;
}