#include <iostream>
using namespace std;

int main() {
    // from https://ru.stackoverflow.com/a/813631/23044
	int a[] = { -1 };
    int size = sizeof( a ) / sizeof( a[ 0 ] );

	for (int j = 1; j < size; j++)
	{
		for (int i = 0; i < size - j; i++)
		{
			if (a[ i ] > a[ i + 1 ])
			{
				int b = a[ i ];
				a[ i ] = a[ i + 1 ];
				a[ i + 1 ] = b;
			}
		}
	}

	for (int i = 1; i < size; i++)
	{
		if (a[ i ] - a[ i - 1 ] > 1)
		{
			std::cout << a[ i - 1 ] + 1 << "\n";
			break;
		}
	}
}