// Programmer: Shadow1
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using str = string; // yay python!
#define i64 int64_t
#define show(x) cerr << (#x) << " = " << (x) << '\n';
#define output_vector(v) for(auto &x : v){cout << x << ' ';}cout << '\n';
#define output_pairvector(v) for(auto &x : v){cout << x.first << " " << x.second << '\n';}
#define vt vector
#define pq priority_queue
#define pb push_back
#define eb emplace_back
#define pii pair<int,int>
#define umap unordered_map
#define uset unordered_set
#define fir first
#define sec second
#define sz(x) ll(x.size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define int ll
#define discretize(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
// T: O(n^3)
// M : O(n + k log n)
void solve() {
int n, q;
cin >> n >> q;
vector<int> cnt(n);
while(q--) {
int x; cin >> x;
if(x > 0)
cnt[x]++;
}
int ans = *max_element(all(cnt))-1;
ans = max(0ll, ans);
cout << ans << '\n';
}
signed main() {
// freopen("output.txt", "w", stdout);
// freopen("input.txt", "r", stdin);
ios::sync_with_stdio(false);
cin.tie(NULL);
int T = 1;
// cin >> T;
while(T--)
solve();
return 0;
}
/* CHECK :
1. COMPARATOR FUNCTION MUST RETURN FALSE WHEN ARGUMENTS ARE EQUAL!!!
2. Overflow! Typecase int64_t on operations if varaibles are int
3. Check array bounds!!!
4. Check array indexing!!!
5. Edge cases. (N==1)!!!
*/
