#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
long long a[110];
int main() {
    long long n, k;
    cin >> n >> k;
    for (int i = 0; i < k; i++) {
        cin >> a[i];
    }
    bool b = true;
    for (int i = 1; i < k; i++) {
        if (a[i - 1] == a[i] - 1 && a[i] % 5 == 0) {
            b = false;
        }
    }
    if (b) {
        cout << "Yes" << endl;
    }
    else {
        cout << "No" << endl;
    }
    return 0;
}