#include <bits/stdc++.h>
using namespace std;

int main(){
  int customer;
  int apple;
  int banana;
  
  int end;
  
  cin >> customer >> apple >> banana;
  
  for (end = 1; end < customer ; end++){
  	if(apple == 0 || banana == 0) {
  		cout << end;
  		return 0;
  	}
  	
  	int crape;
  	cin >> crape;
  	
  	switch (crape){
  		case 1:
  			apple--;
  			break;
  		
  		case 2:
  			banana--;
  			break;
  		
  		case 3:
  			apple--;
  			banana--;
  			break;
  	}
  }
  
  cout << -1;
}