#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int searchVal; int numValues; int input;
    vector<int> listVal;
    cin >> searchVal >> numValues;
    for (int i = 0; i < numValues; i++) {
        cin >> input;
        listVal.push_back(input);
    }
    int pivot = numValues / 2;
    bool isFound = false;
    int startPos = 0; int endPos = numValues - 1;
    while (pivot >0 && !isFound) {
        int pivot = (endPos - startPos) / 2;
        if (listVal[pivot] == searchVal) {
            isFound = true;
            cout << pivot << endl;
        }
        else if (listVal[pivot] > searchVal) {
            endPos = pivot;
        }

        else {
            startPos = pivot;
        }
    }
    return 0;
}