#include<sstream>
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<queue>
#include<numeric>
#include<functional>
#include<algorithm>
#include<bitset>
using namespace std;
#define INF (1<<29)
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()
#define uniq(v) v.erase(unique(all(v)),v.end())
#define indexOf(v,x) (find(all(v),x)-v.begin())




int main(){
	int b,n,c[10],ans=INF;
	cin>>b>>n;
	rep(i,n)cin>>c[i];
	rep(i,n){
		int h=b,s=0;
		rep(j,n){
			s+=abs(c[i]-c[j]);
			h+=c[j]-c[i];
		}
		if(0<=h)ans=min(ans,s);
	}
	cout<<ans<<endl;
	return 0;
}