2021-luvut

input/code.cpp: In function 'void addThousand(std::__cxx11::string&)':
input/code.cpp:23:15: error: 'count' is not a member of 'std'
   while (std::count(s.begin(), s.end(), '2') < 2)
               ^~~~~
input/code.cpp:23:15: note: suggested alternative: 'cout'
   while (std::count(s.begin(), s.end(), '2') < 2)
               ^~~~~
               cout

#include <string>
#include <iostream>
 
 
void addThousand(std::string& s) {
	int size = s.size();
 
	std::string fh = s.substr(0, size - 3);
	std::string sh = s.substr(size - 3, 4);
 
 
	if (fh == "")
	{
		s = "1" + sh;
	}
	else {
		long long l = std::stoll(fh);
		l++;
 
		std::string ls = std::to_string(l);
 
		s = ls + sh;
		while (std::count(s.begin(), s.end(), '2') < 2)
		{
			l++;
			ls = std::to_string(l);
			s = ls + sh;
		}
 
 
		/*if (s[0] == '2' && fh[0] != '2')
		{
			int it = 1;
			while (s[it] != '2') {
				it++;
			}
			s[it] = '0';
		}*/
	}
}
 
void addHundred(std::string& s) {
	int size = s.size();
 
	if (s[size - 3] == '0')
	{
		if (s[size - 4] == '0')
		{
			s[size - 3] = '1';
		}
 
		else //if (s[size - 4] == '2')
		{
			std::string fh = s.substr(0, size - 3);
 
			if (s[size - 4] == '1' && fh.find('0') != std::string::npos)
			{
				s[size - 3] = '1';
			}
			else
			{
				addThousand(s);
 
			}
 
			return;
		}
	}
	else if (s[size - 3] == '9') {
		s[size - 3] = '0';
		addThousand(s);
		return;
	}
	else
	{
		s[size - 3]++;
	}
}
 
void addTen(std::string& s) {
	int size = s.size();
 
	if (s[size - 2] == '2')
	{
		if (s[size - 3] == '0')
		{
			addHundred(s);
			return;
		}
		else if (s[size - 3] == '1')
		{
			s[size - 2] = '0';
			addHundred(s);
			return;
		}
		else if (s[size - 3] == '2')
		{
			s[size - 2]++;
		}
		else
		{
			addHundred(s);
		}
	}
	else if (s[size - 2] == '9')
	{
		s[size - 2] = '2';
		s[size - 3] = '3';
	}
	else {
		s[size - 2]++;
	}
}
 
void addOne(std::string& s) {
	int size = s.size();
	if (s[size - 1] == '1')
	{
		if (s[size - 2] == '0')
		{
			s[size - 1] = '0';
			s[size - 2] = '1';
			return;
		}
		else if (s[size - 2] == '1')
		{
			s[size - 1] = '2';
			return;
		}
		else
		{
			addTen(s);
			return;
		}
	}
	else if (s[size - 1] == '9')
	{
		s[size - 1] = '1';
		addTen(s);
	}
	else {
		s[size - 1]++;
	}
}
 
 
int main() {
	int n;
	std::cin >> n;
 
 
	std::string s = "2021";
 
	for (int i = 0; i < n - 1; i++)
	{
		addOne(s);
	}
	std::cout << s;
}