#include <iostream>
#include <string>
#include <vector>

/*
ascii 0 := 48, 9 := 57, A := 65, Z := 90
*/

class Nnumbers
{
	public:
	
	std::vector<char> number;
	std::vector<int> number_decimal;
	
	int max_number;
	
	unsigned long long decimal;
	
	void initializeNumberDecimal(void)
	{
		number_decimal.resize(number.size());
		
		return;
	}
	
	void getMaxNumber(void)
	{
		char max_lit = '1';
		
		for(int i = 0; i < number.size(); i ++)
		{
			if((int)max_lit < (int)number[i])
			{
				//std::cout << "yes" << std::endl;
				max_lit = number[i];
			}
		}
		
		if(48 <= (int)max_lit && (int)max_lit <= 57)
		{
			max_number = (int)max_lit - 48;
		}
		else
		{
			max_number = (int)max_lit - 55;
		}
		
		return;
	}
	
	void getNumberDecimal(void)
	{
		for(int i = 0; i < number.size(); i ++)
		{
			if(48 <= (int)number[i] && (int)number[i] <= 57)
			{
				number_decimal[i] = (int)number[i] - 48;
			}
			else
			{
				number_decimal[i] = (int)number[i] - 55;
			}
		}
		
		return;
	}
	
	void getDecimal(void)
	{
		decimal = 0;
		unsigned long long beki = 1;
		
		getMaxNumber();
		
		int numbers = number.size();
		
		for(int i = numbers - 1; i >= 0; i --)
		{
			//std::cout << MAX_NUMBER << " " << beki << std::endl;
			decimal +=  number_decimal[i] * beki;
		
			beki = beki * (max_number + 1);
		}
		
		return;
	}
};



int main(void)
{
	int N;
	
	std::cin >> N;
	
	Nnumbers Nnumber[N];
	
	std::string str[N];
	
	for(int i = 0; i < N; i ++)
	{
		std::cin >> str[i];
		
		int sizenumber = str[i].size();
		
		for(int j = 0; j < sizenumber; j ++)
		{
			Nnumber[i].number.push_back(str[i][j]);
		}
	}
	
	
	for(int i = 0; i < N; i ++)
	{
		Nnumber[i].initializeNumberDecimal();
		Nnumber[i].getNumberDecimal();
		Nnumber[i].getDecimal();
	}
	
	unsigned long long MIN_NUMBER = Nnumber[0].decimal;
	
	for(int i = 1; i < N; i ++)
	{
		if(MIN_NUMBER > Nnumber[i].decimal)
		{
			MIN_NUMBER = Nnumber[i].decimal;
		}
	}
	
	//for debug
	/*
	for(int i = 0; i < N; i ++)
	{
		std::cout << Nnumber[i].decimal << std::endl;
	}
	*/
	
	std::cout << MIN_NUMBER << std::endl;
	
	

	return 0;
}