#include <cstdio>
#include <algorithm>
using namespace std;
int main(){
    int N, C, c, sum = 0, res;
    scanf("%d %d", &N, &C);
    for (int i = 0; i < C; i++) {
        scanf("%d", &c);
        sum+=c;
    }
    res = sum / (N+1), sum%=N+1;
    (sum > 0) ? printf("%d\n", res+1) : printf("%d\n", res);
    return 0;
}


