#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
int b,n;
int c[10];
ll ans=1e18;
ll calc(int a){
	ll have=b;
	ll tem=0;
	for(int i=0;i<n;i++){
		tem+=abs(a-c[i]);
		have+=c[i]-a;
	}
	if(have<0)	return (ll)1e19;
	ans=min(ans,tem);
	return tem;
}
int main(){
	cin>>b>>n;
	for(int i=0;i<n;i++)	cin>>c[i];
	ll l=0,h=1e9;
	while(h-l>100){
		ll lm=(2*l+h)/3;
		ll hm=(l+2*h)/3;
		if(calc(hm)>=calc(lm))	h=hm;
		else 	l=lm;
	}
	for(int i=l;i<=h;i++)	calc(i);
	cout<<ans<<endl;
	return 0;
}