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#include <stdlib.h>
#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include <set>

int n;

typedef std::set< int > ints;

std::vector< ints > groups;
std::vector< bool > groups_ok;
std::vector< ints > links;
std::set< int > unset;
std::set< int > groups_left;

void read_input()
{
	std::cin >> n;
	
	links.resize( n + 1 );

	for ( int i = 1; i <= n; ++i )
	{
		unset.insert( i );
	}

	std::string line;
	std::getline( std::cin, line );
	std::getline( std::cin, line );
	std::istringstream cin( line );
	
	std::string s;
	char c;
	do
	{
		ints group;
		
		cin >> c;
		bool end_of_group = false;
		do
		{
			cin >> s;
			end_of_group = s[ s.length() - 1 ] == ')';
			if ( end_of_group )
			{
				s.resize( s.length() - 1 );
			}
			const bool neg = s[ 0 ] == '~';
			const int value = atoi( s.c_str() + ( neg ? 2 : 1 ) );
			
			const int neg_value = neg ? -value : value;
			
			group.insert( neg_value );

			int link = groups.size();
			if ( neg )
			{
				link = -( link + 1 );
			}
			links[ value ].insert( link );
			
			cin >> c;
		} while ( !end_of_group );
		
		groups_left.insert( groups.size() );
		groups.emplace_back( std::move( group ) );
		
	} while ( !cin.eof() );
	
	groups_ok.resize( groups.size(), false );
}

bool exclude_trivial( const int group_id )
{
	const ints& group = groups[ group_id ];

	const int neg_value = *group.begin();
	const bool neg = neg_value < 0;
	const int value = neg ? -neg_value : neg_value;

	unset.erase( value );
	
	for ( const int _linked_group_id : links[ value ] )
	{
		const bool neg_link = _linked_group_id < 0;
		const int linked_group_id = neg_link ? -( _linked_group_id + 1 ) : _linked_group_id;
		ints& linked_group = groups[ linked_group_id ];
		if ( neg_link == neg )
		{
			groups_ok[ linked_group_id ] = true;
			groups_left.erase( linked_group_id );
			linked_group.erase( neg_value );
		}
		else
		{
			linked_group.erase( -neg_value );
			if ( linked_group.empty() )
			{
				return false;
			}
		}
	}
	
	for ( const int _linked_group_id : links[ value ] )
	{
		const bool neg_link = _linked_group_id < 0;
		const int linked_group_id = neg_link ? -( _linked_group_id + 1 ) : _linked_group_id;
		if ( !groups_ok[ linked_group_id ] && groups[ linked_group_id ].size() == 1 )
		{
			if ( !exclude_trivial( linked_group_id ) )
			{
				return false;
			}
		}
	}

	return true;
}

bool exclude_trivial()
{
	for ( int i = 0; i < groups.size(); ++i )
	{
		if ( !groups_ok[ i ] && groups[ i ].size() == 1 && !exclude_trivial( i ) )
		{
			return false;
		}
	}
	return true;
}

#define MOD ( 1000000000 + 7 )

int calc_result( int pow )
{
	int result = 1;
	while ( pow )
	{
		result *= 2;
		result = ( result % MOD );
		--pow;
	}
	return result;
}

int rec()
{
	const ints& group = groups[ *groups_left.begin() ];

	const int neg_value = *group.begin();
	const bool neg = neg_value < 0;
	const int value = neg ? -neg_value : neg_value;

	unset.erase( value );

	// true case
	
	bool no_solution = false;
	for ( const int _linked_group_id : links[ value ] )
	{
		const bool neg_link = _linked_group_id < 0;
		const int linked_group_id = neg_link ? -( _linked_group_id + 1 ) : _linked_group_id;
		ints& linked_group = groups[ linked_group_id ];
		if ( neg_link == neg )
		{
			groups_left.erase( linked_group_id );
			linked_group.erase( neg_value );
		}
		else
		{
			linked_group.erase( -neg_value );
			if ( linked_group.empty() )
			{
				no_solution = true;
				break;
			}
		}
	}
	
	int true_result = 0;
	if ( !no_solution )
	{
		if ( groups_left.empty() )
		{
			true_result = calc_result( unset.size() );
		}
		else
		{
			true_result = rec();
		}
	}

	for ( const int _linked_group_id : links[ value ] )
	{
		const bool neg_link = _linked_group_id < 0;
		const int linked_group_id = neg_link ? -( _linked_group_id + 1 ) : _linked_group_id;
		ints& linked_group = groups[ linked_group_id ];
		if ( neg_link == neg )
		{
			groups_left.insert( linked_group_id );
			linked_group.insert( neg_value );
		}
		else
		{
			linked_group.insert( -neg_value );
		}
	}

	// false case
	
	no_solution = false;
	for ( const int _linked_group_id : links[ value ] )
	{
		const bool neg_link = _linked_group_id < 0;
		const int linked_group_id = neg_link ? -( _linked_group_id + 1 ) : _linked_group_id;
		ints& linked_group = groups[ linked_group_id ];
		if ( neg_link == neg )
		{
			linked_group.erase( neg_value );
			if ( linked_group.empty() )
			{
				no_solution = true;
				break;
			}
		}
		else
		{
			groups_left.erase( linked_group_id );
			linked_group.erase( -neg_value );
		}
	}
	
	int false_result = 0;
	if ( !no_solution )
	{
		if ( groups_left.empty() )
		{
			false_result = calc_result( unset.size() );
		}
		else
		{
			false_result = rec();
		}
	}

	for ( const int _linked_group_id : links[ value ] )
	{
		const bool neg_link = _linked_group_id < 0;
		const int linked_group_id = neg_link ? -( _linked_group_id + 1 ) : _linked_group_id;
		ints& linked_group = groups[ linked_group_id ];
		if ( neg_link == neg )
		{
			linked_group.insert( neg_value );
		}
		else
		{
			groups_left.insert( linked_group_id );
			linked_group.insert( -neg_value );
		}
	}

	// revert

	unset.insert( value );

	const int result = ( true_result + false_result ) % MOD;
	return result;
}

int main()
{
	read_input();
	if ( !exclude_trivial() )
	{
		std::cout << 0;
	}
	else if ( groups_left.empty() )
	{
		std::cout << calc_result( unset.size() );
	}
	else
	{
		std::cout << rec();
	}
	
	return 0;
}