#include<stdio.h>
#define N 100001
long a[N],n,m,i;
long long s=0;
int main()
{freopen("grupuri.in","r",stdin);
freopen("grupuri.out","w",stdout);
scanf("%ld%ld",&n,&m);
for(i=1;i<=m;i++)
       scanf("%ld",&a[i]),s+=a[i];
if(s/n>=a[m])
       {printf("%lld",s/n);
       return 0;}
for(i=m;i;i--)
       {s-=a[i];
       if(s/n>=a[i-1])
              {printf("%lld",s/n);
              return 0;}}
printf("0");
return 0;}