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

int main() {
	int b,n;cin>>b>>n;
	vector<int>c(n);
	long long sum=0,ans=0;
	for(int i=0;i<n;i++){
		cin>>c[i];
		sum+=c[i];
	}
	int amari = sum%n,average;
	if(b>= n-amari && amari > n/2.){
		average = (sum+(n-amari))/n;
	}else average = sum/n;
	
	for(int i=0;i<n;i++){
		ans+=abs(c[i]-average);
	}
	
	cout<<ans<<endl;
	
	return 0;
}