#include<stdio.h>
int m,v[100004],n,k,l1,l2;
int f(int x)
{
    long long s=0;
    for(int i=n;i>=1&&s<=(long long)k*x;i--)
    {
        if(x<v[i])
            s+=x;
        else
            s+=v[i];

    }
    if(s<=(long long)k*x)
            return 0;
        else return 1;


}
int main()
{
    freopen("grupuri.in","r",stdin);
    freopen("grupuri.out","w",stdout);
    scanf("%d%d",&k,&n);
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&v[i]);
        l2+=v[i];
    }
    l1=1;
    l2++;
    while(l1<=l2)
    {
        m=(l1+l2)/2;
        if(f(m)==0)
        l2=m-1;
        else l1=m+1;
    }
    printf("%d",l1);

    return 0;
}