#include <stdio.h>
#define MAXN 100000
int n, k, v[MAXN];
inline long long min2(long long a, int b){
    if(a<b){
        return a;
    }
    return b;
}
inline int ok(long long p){
    int i;
    long long sum=0;
    for(i=0; i<n; i++){
        sum+=min2(p, v[i]);
    }
    return (sum>=(p*(long long)k));
}
int main(){
    long long rez, pas;
    int i;
    FILE *fin, *fout;
    fin=fopen("grupuri.in", "r");
    fout=fopen("grupuri.out", "w");
    fscanf(fin, "%d%d", &k, &n);
    for(i=0; i<n; i++){
        fscanf(fin, "%d", &v[i]);
    }
    rez=0;
    for(pas=1LL<<36; pas!=0; pas>>=1){
        if(ok(rez+pas)==1){
            rez+=pas;
        }
    }
    fprintf(fout, "%lld\n", rez);
    fclose(fin);
    fclose(fout);
    return 0;
}