#include <iostream>
#include <vector>
using namespace std;

int main() {
    int N, Visina;
        cin >> N >> Visina; 

            vector<int> Stalaktiti(N);  
                for (int i = 0; i < N; ++i) {
                        cin >> Stalaktiti[i];  
                            }

                                
                                    for (int i = 0; i < N; ++i) {
                                            if (Stalaktiti[i] <= Visina) { 
                                                    
                                                                cout << i + 1 << endl; 
                                                                            
                                                                                        return 0;
                                                                                                }
                                                                                                    }

                                                                                                        
                                                                                                            cout << -1 << endl;
                                                                                                                return 0;
                                                                                                                }