#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const ll MOD1000000007 = 1000000007;
const ll MOD998244353 = 998244353;
const ll MOD[3] = {999727999, 1070777777, 1000000007};
const ll LINF = 1LL << 60LL;
const int IINF = (1 << 30) - 2;


void solve(){
    int n, m; cin >> n >> m;
    set<string> st;
    for(int i=0; i<m; i++){
        string s; cin >> s;
        st.insert(s);
    }

    if((int)st.size() == (1<<n)){
        cout << "Yes\n";
    }else{
        cout << "No\n";
    }
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    int T=1;
    //cin >> T;
    while(T--) solve();
}