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

#define SIZE_OF_ARRAY(x) (sizeof(x) / sizeof(*(x)))

typedef unsigned int uint;

static char get_char_buffer[4 * 1024];
static std::size_t get_char_buffer_i = SIZE_OF_ARRAY(get_char_buffer);
static std::size_t get_char_buffer_n = SIZE_OF_ARRAY(get_char_buffer);

static char get_char_prefix = 0;
static char get_char_result = 0;

int get_char()
{
	get_char_result = 0;

	if (get_char_prefix)
	{
		get_char_result = get_char_prefix;

		get_char_prefix = 0;
	}
	else if (get_char_buffer_n == 0)
	{
		get_char_result = std::char_traits<char>::eof();
	}
	else if (get_char_buffer_i < get_char_buffer_n)
	{
		get_char_result = get_char_buffer[get_char_buffer_i++];
	}
	else
	{
		std::cin.read(get_char_buffer, SIZE_OF_ARRAY(get_char_buffer));

		get_char_buffer_i = 0;
		get_char_buffer_n = std::cin.gcount();

		return get_char();
	}

	return get_char_result;
}

void unget_char()
{
	get_char_prefix = get_char_result;
}

uint get_uint()
{
	int c;
	while (isspace(c = get_char()));

	uint value = (c - '0');

	while (isdigit(c = get_char()))
	{
		value = (10 * value) + (c - '0');
	}

	return value;
}

typedef std::vector<int> lit_t;

lit_t get_lit()
{
	lit_t result;

	int c;
	while (isspace(c = get_char()));

	if (c != '(')
	{
		return result;
	}

	while (true)
	{
		while (isspace(c = get_char()));

		if (c == ')')
		{
			break;
		}

		int mul = 1;
		if (c == '~')
		{
			mul = -1;
			while (isspace(c = get_char()));
		}

		int val = mul * get_uint();

		result.push_back(val);

		unget_char();

		while (isspace(c = get_char()));

		if (c == ')')
		{
			break;
		}
	}

	return result;
}

typedef std::vector<lit_t> expr_t;

expr_t get_expr()
{
	expr_t result;

	lit_t lit;
	while ((lit = get_lit()).size() > 0)
	{
		result.push_back(lit);

		int c;
		while (isspace(c = get_char()));

		if (c != '^')
		{
			break;
		}
	}

	return result;
}

uint get_bit(uint n, uint k)
{
	return (n & (1 << k)) >> k;
}

uint eval(lit_t &lit, uint val)
{
	for (uint i = 0; i < lit.size(); ++i)
	{
		int a = lit[i];

		int bit = 0;
		bool _not = false;

		if (a < 0)
		{
			bit = (-a) - 1;
			_not = true;
		}
		else
		{
			bit = a - 1;
			_not = false;
		}

		uint result = _not ^ get_bit(val, bit);

		if (result)
		{
			return 1;
		}
	}

	return 0;
}

uint eval(expr_t &expr, uint val)
{
	for (uint i = 0; i < expr.size(); ++i)
	{
		uint result = eval(expr[i], val);

		if (result == 0)
		{
			return 0;
		}
	}

	return 1;
}

int main()
{
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(0);

	uint n = get_uint();

	expr_t expr = get_expr();

	uint result = 0;

	uint nn = 1 << n;

	for (uint i = 0; i < nn; ++i)
	{
		result += eval(expr, i);
	}

	std::cout << result % 1000000007 << "\n";

	return 0;
}