#include <fstream>
using namespace std;
ifstream f("grupuri.in");
ofstream g("grupuri.out");
int n,k,i,v[1<<20];
long long sol,step,s;
bool check(long long x)
{
    long long sum=0;
    for(i=1;i<=n;++i)
        sum+=((x<v[i])?x:v[i]);
    return sum>=x*k;
}
int main()
{
    f>>k>>n;
    for(i=1;i<=n;++i) f>>v[i],s+=v[i];
    for(step=1LL<<60;step;step>>=1)
        if(sol+step<=s/k&&check(sol+step)) sol+=step;
    g<<sol;
    return 0;
}