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#include <algorithm>
#include <iostream>
#include <cassert>
#include <vector>
#include <cstdio>
#include <array>
#include <deque>
#include <cmath>
#include <stack>
#include <queue>
#include <set>
#include <map>
namespace {
	using namespace std;

	typedef vector<int> vint;
	typedef long long unsigned ulo;
	typedef long long lint;
	
	void __attribute__((unused)) spacje(int k) {
		int magic;
		static stack<int*> stos;
		while (!stos.empty() && stos.top() <= &magic) stos.pop();
		stos.push(&magic);
		for (int n = k * stos.size(); n--;) fprintf(stderr, " ");
	}

    #define BEND(x) begin(x), end(x)
	
	#define BOTH(x) for (int x = 0; x < 2; ++x)
	
	#define UPlt(xx, yy) (xx) = min(xx, yy)
	#define UPgt(xx, yy) (xx) = max(xx, yy)
	
	struct in_t {
		template<class T>
		operator T () {
			static bool __attribute__((unused)) dummy = ios_base::sync_with_stdio(false);
			T x;
			cin >> x;
			return x;
		}
	};
	in_t __attribute__((unused)) in;
	
	class Print {
		ostream & os;
		bool nfirst;
	 public:
		Print(ostream & os = cout) : os(os), nfirst(false) {}
		~Print() { os << endl; }
		template<class T> Print & operator , (T const& e) {
			if (nfirst) os << " ";
            os << e; nfirst = true; return *this;
        }
	};
	
	#define print Print{cout},
	#define prerr Print{cerr},
	
	template <class T>
	struct Range {
		struct Intit {
			T x; Intit(T x) : x(x) {}
			T & operator * () { return x; };
			bool operator != (Intit other) { return x < other.x; }
			void operator ++ () { ++x; }
		};
		
		T b, e;
		explicit Range(T n) : b(0), e(n) {}
		Range(T b, T e) : b(b), e(e) {}
		Intit begin() { return b; }
		Intit end() { return e; }
	};
	
	template <class T>
	Range<T> range(T n) { return Range<T>(n); }
	
	template <class T>
	Range<T> range(T b, T e) { return Range<T>(b, e); }

	template <class T>
	Range<T> inclusive(T b, T e) { return Range<T>(b, e + 1); }
	
	#define _ __attribute__((unused)) _
};

// #define dprintf(...) if (1) spacje(2), fprintf(stderr, __VA_ARGS__)
#define dprintf(...) {}

int const MOD = 1000000007;

vector<int> powers;

struct Node;

Node * chain(int depth, char const * lits, int n);

struct Node {
    Node * left;
    Node * right;
    int sum;
    bool full;

    Node * create(int depth, char const * lits, int n) {
        dprintf("create %d .. %d\n", depth, n);
        if (full) {
            return this;
        }
        if (n == 0) {
            return new Node {
                nullptr, nullptr, powers[depth], true,
            };
        } else {
            Node * new_left = lits[0] ? left : (left ? left->create(depth - 1, lits + 1, n - 1) : chain(depth - 1, lits + 1, n - 1));
            Node * new_right = lits[0] ? (right ? right->create(depth - 1, lits + 1, n - 1) : chain(depth - 1, lits + 1, n - 1)) : right;
            int sum = (new_left ? new_left->sum : 0) + (new_right ? new_right->sum : 0);
            if (sum >= MOD) sum -= MOD;
            bool full = sum == powers[depth];
            return new Node { new_left, new_right, sum, full };
        }
    }
};

Node * chain(int depth, char const * lits, int n) {
    dprintf("chain %d .. %d\n", depth, n);
    int sum = powers[depth - n];
    if (n == 0) {
        return new Node { nullptr, nullptr, sum, true };
    }
    Node * left = lits[0] ? nullptr : chain(depth - 1, lits + 1, n - 1);
    Node * right = lits[0] ? chain(depth - 1, lits + 1, n - 1) : nullptr;
    return new Node { left, right, sum, false };
}

int main() {
    vector<pair<int, vector<char>>> clauses;

    int n = in;
    powers.push_back(1);
    for (int _ : range(n)) {
        int x = powers.back();
        x *= 2;
        if (x >= MOD) x -= MOD;
        powers.push_back(x);
    }

    while (true) {
        char c = in;
        if (cin) {
            assert(c == '(');
            dprintf("klauzula\n");
            vector<pair<int, bool>> lits;
            while (true) {
                char c = in;
                if (c == ')') break;
                bool val = true;
                if (c == '~') {
                    val = false;
                    c = in;
                }
                assert(c == 'x');
                int i = in;
                lits.push_back({-i, val});
                c = in;
                dprintf("%d %d\n", i, val);
                if (c == ')') break;
                assert(c == 'v');
            }
            sort(BEND(lits));
            vector<char> clause;
            for (auto p : lits) {
                clause.push_back(p.second);
            }
            clauses.push_back({-lits.front().first, clause});
            c = in;
            if (cin) assert(c == '^');
            else break;
        }
    }
    sort(BEND(clauses), [](pair<int, vector<char>> const& fst, pair<int, vector<char>> const& snd){
            return fst.first < snd.first;
            });

    Node * root = new Node { nullptr, nullptr, 0, false };
    int depth = 0;

    for (auto const& clause : clauses) {
        int mydepth = clause.first;
        dprintf("%d -> %d\n", depth, mydepth);
        vector<char> const& vals = clause.second;
        int offset = mydepth - depth;
        int o2 = min(offset, (int)vals.size());
        dprintf("dół\n");
        Node * new_root = root->create(depth, vals.data() + o2, vals.size() - o2);

        while (mydepth - depth > (int)vals.size()) {
            dprintf("zapełniam dziurę\n");
            root = new Node { root, root, 2 * root->sum % MOD, root->full };
            new_root = new Node { new_root, new_root, 2 * new_root->sum % MOD, new_root->full };
            dprintf("dodaję (rootsum %d, newrootsum %d\n", root->sum, new_root->sum);
            depth++;
        };
        int i = mydepth - depth - 1;
        while (mydepth > depth) {
            dprintf("ogon\n");
            Node * left = vals[i] ? root : new_root;
            Node * right = vals[i] ? new_root : root;
            //Node * right = vals[i] ? root : new_root;
            //Node * left = vals[i] ? new_root : root;
            int sum = (left->sum + right->sum) % MOD;
            bool full = root->full && new_root->full;
            new_root = new Node { left, right, sum, full };
            root = new Node { root, root, 2 * root->sum % MOD, root->full };
            --i;
            depth++;
            dprintf("dodaję (rootsum %d, newrootsum %d\n", root->sum, new_root->sum);
        }
        root = new_root;
    }

    int zlych = root->sum;
    while (depth < n) {
        zlych *= 2;
        zlych %= MOD;
        depth++;
    }
    
    int dobrych = powers[n];
    dobrych += MOD;
    dobrych -= zlych;
    dobrych %= MOD;
    print dobrych;
	
	return 0;
}