#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
const ll mod = 1000000007;
const ll INF = (1e+18) + 7;
typedef pair<int, int>P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-6;
const ld pi = acos(-1.0);
//typedef vector<vector<ll>> mat;
typedef vector<int> vec;

ll mod_pow(ll a, ll n) {
	ll res = 1;
	while (n) {
		if (n & 1)res = res * a%mod;
		a = a * a%mod; n >>= 1;
	}
	return res;
}

struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n%mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint &a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint &a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint &a, modint b) { a.n = ((ll)a.n*b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, int n) {
	if (n == 0)return modint(1);
	modint res = (a*a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p%a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }

//const int max_n = 1 << 22;
//modint fact[max_n], factinv[max_n];
//void init_f() {
//	fact[0] = modint(1);
//	for (int i = 0; i < max_n - 1; i++) {
//		fact[i + 1] = fact[i] * modint(i + 1);
//	}
//	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
//	for (int i = max_n - 2; i >= 0; i--) {
//		factinv[i] = factinv[i + 1] * modint(i + 1);
//	}
//}
//modint comb(int a, int b) {
//	if (a < 0 || b < 0 || a < b)return 0;
//	return fact[a] * factinv[b] * factinv[a - b];
//}

int w, n;
void solve() {
	vector<int> x(n);
	vector<ll> rx(n + 1);
	rep(i, n)cin >> x[i];
	rep(i, n)rx[i + 1] = rx[i] + x[i];
	int le = 0, ri = w;
	while (ri - le > 1) {
		ll m = (le + ri) / 2;
		vector<int> exi(n + 2, 0);
		exi[0] = 1; exi[1] = -1;
		rep(i, n) {
			exi[i + 1] += exi[i];
			if (exi[i]) {
				{
					ll sum = rx[n] - rx[i];
					ll rest = w - sum;
					ll cnt = n - i;
					if (cnt <= rest) {
						exi[n] = true; break;
					}
				}
				int memol, memor;
				//leftside
				int l = i-1, r = n + 1;
				while (r - l > 1) {
					int mid = (l + r) / 2;
					ll sum = rx[mid] - rx[i];
					ll rest = w - sum;

					ll cnt = mid - i;
					if (rest > (cnt - 1)*m)l = mid;
					else r = mid;
				}
				memol = r;
				//rightside
				l = i, r = n + 1;
				while (r - l > 1) {
					int mid = (l + r) / 2;
					ll sum = rx[mid] - rx[i];
					ll rest = w - sum;
					ll cnt = mid - i;
					if (rest < (cnt - 1))r = mid;
					else l = mid;
				}
				memor = l;
				if (memol <= memor) {
					exi[memol]++;
					exi[memor + 1]--;
				}
				//cout << m << "! " << i << " " << memol << " " << memor << endl;
			}
		}
		if (exi[n]) {
			ri = m;
		}
		else le = m;
	}
	//cout << "ans is ";
	cout << ri << endl;
}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(12);
	//init_f();
	//int t; cin >> t; rep(i, t)solve();
	while (cin >> w >> n, w | n)solve();
	//solve();
	stop
		return 0;
}



Measured memory_bytes: 3636