#include <bits/stdc++.h>

using namespace std;

int main()
{
    int n, k;
    cin >> n >> k;

    vector<bool> marVolt(n + 1, 0);
    vector<int> eredeti(k, 0);
    priority_queue<int, vector<int>, greater<int>> sorrend;

    for(int i = 0; i < k; i++){
        cin >> eredeti[i];
        sorrend.push(eredeti[i]);
    }

    int valasz = 0;
    for(int i = 0; i < k; i++){
        if(marVolt[eredeti[i]]) continue;

        int ki = 0;
        while(!sorrend.empty() && sorrend.top() < eredeti[i]){
            if(!marVolt[sorrend.top()]){
                marVolt[sorrend.top()] = 1;
                ki++;
            }

            sorrend.pop();
        }

        if(ki){
            valasz++;
        }

        marVolt[eredeti[i]] = 1;
    }

    cout << valasz << "\n";
}