#include <bits/stdc++.h>
using namespace std;
 
int main() {
 
	int n;
	cin>>n;
 
	vector<int> numbers(n);
 
	for(auto& number: numbers){
		cin>>number;
	}
 
	map<int,int> freq;
 
	for(int i=0; i<n; i++){
		freq[numbers[i]]++;
	}
 
	vector<pair<int,int>> g;
 
	for(auto it= freq.begin(); it!= freq.end(); it++){
		int u = it->first;
		int v = it->second;
 
		g.push_back({u,v});
	}
 
	int steps = 0;
 
	for(int i=g.size() - 1; i > 0; i--){
		steps += (steps + g[i].second);
	}
 
	cout<<steps;
 
	return 0;
}

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