#include<cstdio>#include<cmath>#include<iostream>using namespace std;const double eps = 1e-8;int m,n;double patient[1005];int sig(double k){ if(fabs(k)<eps) return 0; return k>0?1:-1;}int main(){ while(scanf("%d%d",&m,&n)!=EOF){ double sum = 0,maxx = 0; for(int i=0;i<n;i++){ scanf("%lf",&patient[i]); sum+=patient[i]; } double l = 0,r = sum; double ans = 0; while(sig(r-l)){ double user = 0;double mid = (l+r)/2; for(int i=0;i<n;i++){ user+=min(patient[i],mid); } if(sig(user-mid*m)<0)r=mid; else{ l = mid; } } printf("%.4lfn",sum-r*(m-1)); }}
