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/* 2016
 * Maciej Szeptuch
 */
#include <cstdio>
#include <vector>
#include <cctype>

const int MAX_BUFFER    = 16384;
const int MAX_VARIABLES = 1048576;
const long long int MOD = 1000000007LL;

struct Variable
{
    std::vector<int> clauses;
};

struct Clause
{
    int start;
    int end;
    int length;
};

class iTree
{
private:
    static const int TREE_SIZE = MAX_VARIABLES;
    int data[TREE_SIZE * 2];
    std::pair<int, int> max[TREE_SIZE * 2];

public:
    iTree();

    void add(int start, int end);
    void remove(int start, int end);
    void insert(int start, int end, int value, int iStart=0, int iEnd=TREE_SIZE-1, int iPos=1);
    std::pair<int, int> get_max(void) const;

private:
    void propagate(int iPos);
};

Clause clause[MAX_VARIABLES];
int clauses;
iTree tree;
Variable variable[MAX_VARIABLES];
char buffer[MAX_BUFFER];
int variables;
long long int power_table[MAX_VARIABLES];
std::vector<int> dropped_clauses;
bool clause_dropped[MAX_VARIABLES];

void feed(const char *input);
long long int solve(int variables_set=0);

int main(void)
{
    scanf("%d", &variables);
    power_table[0] = 1;
    for(int v = 1; v < variables; ++ v)
    {
        power_table[v] = power_table[v - 1] * 2;
        if(power_table[v] > MOD)
            power_table[v] %= MOD;
    }

    while(scanf("%16383s", buffer) != -1)
        feed(buffer);

    printf("%lld\n", solve());
    return 0;
}

long long int solve(int variables_set)
{
    auto best = tree.get_max();
    if(best.second == 0)
        return power_table[variables - variables_set];

    Variable &var = variable[best.first];

    char singleton = 0;
    for(auto clause_id: var.clauses)
    {
        bool negation = false;
        if(clause_id < 0)
        {
            negation = true;
            clause_id *= -1;
        }

        if(clause_dropped[clause_id])
            continue;

        -- clause_id;
        if(clause[clause_id].length == 1)
        {
            if(singleton == 1 + !negation)
                return 0;

            singleton = 1 + negation;
        }
    }

    for(int c = 0; c < (int) var.clauses.size(); ++ c)
    {
        int clause_id = var.clauses[c];
        if(clause_id < 0)
            clause_id *= -1;

        -- clause[clause_id - 1].length;
    }

    int drop = 0;
    int result = 0;
    if(singleton == 0 || singleton == 1)
    {
        // Try x_n = T
        for(int c = 0; c < (int) var.clauses.size(); ++ c)
        {
            int clause_id = var.clauses[c];
            if(clause_id < 0)
                continue;

            if(clause_dropped[clause_id])
                continue;

            dropped_clauses.push_back(clause_id);
            clause_dropped[clause_id] = true;
            tree.remove(clause[clause_id - 1].start, clause[clause_id - 1].end);
            ++ drop;
        }

        tree.insert(best.first, best.first, -var.clauses.size());
        result += solve(variables_set + 1);
        tree.insert(best.first, best.first, var.clauses.size());

        for(int d = 0; d < drop; ++ d)
        {
            int clause_id = dropped_clauses.back();
            dropped_clauses.pop_back();
            clause_dropped[clause_id] = false;
            tree.add(clause[clause_id - 1].start, clause[clause_id - 1].end);
        }
    }

    if(singleton == 0 || singleton == 2)
    {
        // Try x_n = F
        drop = 0;
        for(int c = 0; c < (int) var.clauses.size(); ++ c)
        {
            int clause_id = var.clauses[c];
            if(clause_id > 0)
                continue;

            clause_id *= -1;
            if(clause_dropped[clause_id])
                continue;

            dropped_clauses.push_back(clause_id);
            clause_dropped[clause_id] = true;
            tree.remove(clause[clause_id - 1].start, clause[clause_id - 1].end);
            ++ drop;
        }

        tree.insert(best.first, best.first, -var.clauses.size());
        result += solve(variables_set + 1);
        tree.insert(best.first, best.first, var.clauses.size());
        if(result > MOD)
            result %= MOD;

        for(int d = 0; d < drop; ++ d)
        {
            int clause_id = dropped_clauses.back();
            dropped_clauses.pop_back();
            clause_dropped[clause_id] = false;
            tree.add(clause[clause_id - 1].start, clause[clause_id - 1].end);
        }
    }

    for(int c = 0; c < (int) var.clauses.size(); ++ c)
    {
        int clause_id = var.clauses[c];
        if(clause_id < 0)
            clause_id *= -1;

        ++ clause[clause_id - 1].length;
    }

    return result;
}

inline
iTree::iTree()
:data()
,max()
{
    for(int s = 0; s < TREE_SIZE; ++ s)
        max[s + TREE_SIZE].first = s;

    for(int s = TREE_SIZE - 1; s > 0; -- s)
        max[s] = max[s * 2 + (max[s * 2 + 1].second > max[s * 2].second ? 1 : 0)];
}

inline
void iTree::add(int start, int end)
{
    insert(start, end, 1);
}

inline
void iTree::remove(int start, int end)
{
    insert(start, end, -1);
}

inline
std::pair<int, int> iTree::get_max(void) const
{
    return max[1];
}

inline
void iTree::insert(int start, int end, int value, int iStart, int iEnd, int iPos)
{
    if(start == iStart && end == iEnd)
    {
        data[iPos] += value;
        max[iPos].second += value;
        propagate(iPos / 2);
        return;
    }

    int iMid = (iStart + iEnd) / 2;
    if(end <= iMid)
        insert(start, end, value, iStart, iMid, iPos * 2);

    else if(start > iMid)
        insert(start, end, value, iMid + 1, iEnd, iPos * 2 + 1);

    else
    {
        insert(start, iMid, value, iStart, iMid, iPos * 2);
        insert(iMid + 1, end, value, iMid + 1, iEnd, iPos * 2 + 1);
    }
}

inline
void iTree::propagate(int iPos)
{
    while(iPos > 0)
    {
        max[iPos] = max[iPos * 2 + (max[iPos * 2 + 1].second > max[iPos * 2].second ? 1 : 0)];
        max[iPos].second += data[iPos];
        iPos /= 2;
    }
}

void feed(const char *input)
{
    enum Parser_state
    {
        CLAUSE_BEGIN,
        CLAUSE_END,
        VARIABLE_BEGIN,
        VARIABLE_ID,
    };

    static Parser_state parser_state = CLAUSE_BEGIN;
    static int variable_id = 0;
    static bool negation = false;
    for(; *input; ++ input)
    {
        if(isspace(*input))
            continue;

        switch(parser_state)
        {
            case CLAUSE_BEGIN:
                parser_state = VARIABLE_BEGIN;
                clauses[clause].start = MAX_VARIABLES;
                clauses[clause].end = 0;
                break;

            case VARIABLE_BEGIN:
                if(*input == '~')
                    negation = true;

                else
                {
                    parser_state = VARIABLE_ID;
                    variable_id = 0;
                }
                break;

            case VARIABLE_ID:
                if('0' <= *input && *input <= '9')
                    variable_id = variable_id * 10 + *input - '0';

                else
                {
                    -- variable_id;
                    clause[clauses].start = std::min(clause[clauses].start, variable_id);
                    clause[clauses].end = std::max(clause[clauses].end, variable_id);
                    clause[clauses].length += 1;
                    variable[variable_id].clauses.push_back((clauses + 1) * (negation ? -1 : 1));
                    negation = false;
                    if(*input == 'v')
                        parser_state = VARIABLE_BEGIN;

                    else if(*input == ')')
                    {
                        parser_state = CLAUSE_END;
                        tree.add(clause[clauses].start, clause[clauses].end);
                        ++ clauses;
                    }
                }

                break;

            case CLAUSE_END:
                parser_state = CLAUSE_BEGIN;
                break;
        }
    }
}