#include<iostream>
#include<vector>
using namespace std;

typedef vector<int> vi;
#define rep(i,n) for(int i=0;i<(int)(n);++i)
const int N=17;
int u[N],dp[N];
int main(){
    int t,n;cin>>t>>n;
    vi a(n);rep(i,n)cin>>a[i];
    rep(i,1<<n){
        int s=0;
        rep(j,n)if(i&1<<j)s+=a[j];
        u[i]=s;
    }
    rep(i,1<<n){
        if(i==0)continue;
        int s=(i-1)&i;
        while(1){
            dp[i]=max(dp[i],dp[s]+u[i-s]);
            if(s==0)break;
            s=(s-1)&i;
        }
    }
    cout<<dp[(1<<n)-1]<<endl;
}