5694번: Bingo! ↗

/*
[5694: Bingo!](https://www.acmicpc.net/problem/5694)

Tier: Bronze 1 
Category: bruteforcing, implementation, math
*/


#include <bits/stdc++.h>

using namespace std;

#define for1(s, e) for(int i = s; i < e; i++)
#define for1j(s, e) for(int j = s; j < e; j++)
#define forEach(k) for(auto i : k)
#define forEachj(k) for(auto j : k)
#define sz(vct) vct.size()
#define all(vct) vct.begin(), vct.end()
#define sortv(vct) sort(vct.begin(), vct.end())
#define uniq(vct) sort(all(vct));vct.erase(unique(all(vct)), vct.end())
#define fi first
#define se second
#define INF (1ll << 60ll)

typedef unsigned long long ull;
typedef long long ll;
typedef ll llint;
typedef unsigned int uint;
typedef unsigned long long int ull;
typedef ull ullint;

typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<double, double> pdd;
typedef pair<double, int> pdi;
typedef pair<string, string> pss;

typedef vector<int> iv1;
typedef vector<iv1> iv2;
typedef vector<ll> llv1;
typedef vector<llv1> llv2;

typedef vector<pii> piiv1;
typedef vector<piiv1> piiv2;
typedef vector<pll> pllv1;
typedef vector<pllv1> pllv2;
typedef vector<pdd> pddv1;
typedef vector<pddv1> pddv2;

const double EPS = 1e-8;
const double PI = acos(-1);

template<typename T>
T sq(T x) { return x * x; }

int sign(ll x) { return x < 0 ? -1 : x > 0 ? 1 : 0; }
int sign(int x) { return x < 0 ? -1 : x > 0 ? 1 : 0; }
int sign(double x) { return abs(x) < EPS ? 0 : x < 0 ? -1 : 1; }

bool solve(int n, int b) {
  llv1 ar(b);
  vector<bool> chk(n + 1, false);

  for1(0, b) cin >> ar[i];
  sortv(ar);

  for1(0, b) {
    for1j(i, b) {
      chk[ar[j] - ar[i]] = true;
    }
  }

  for1(0, n + 1) {
    // cout << chk[i] << ' ';
    if(!chk[i]) return false;
  }

  return true;
}

int main() {
  ios::sync_with_stdio(0);
  cin.tie(NULL);cout.tie(NULL);
  while(1) {
    int n, b;
    cin >> n >> b;

    if(n == 0 && b == 0) break;
    bool ret = solve(n, b);

    cout << (ret ? "Y" : "N") << '\n';
  }
}