#include <bits/stdc++.h>
// created [2020/03/08] 00:22:40
#pragma GCC diagnostic ignored "-Wsign-compare"
#pragma GCC diagnostic ignored "-Wsign-conversion"

using i32   = int32_t;
using i64   = int64_t;
using u32   = uint32_t;
using u64   = uint64_t;
using uint  = unsigned int;
using usize = std::size_t;
using ll    = long long;
using ull   = unsigned long long;
using ld    = long double;
template<typename T, usize n>
using arr = T (&)[n];
template<typename T, usize n>
using c_arr = const T (&)[n];
template<typename T>
using max_heap = std::priority_queue<T>;
template<typename T>
using min_heap = std::priority_queue<T, std::vector<T>, std::greater<T>>;
template<typename T> constexpr T popcount(const T u) { return u ? static_cast<T>(__builtin_popcountll(static_cast<u64>(u))) : static_cast<T>(0); }
template<typename T> constexpr T log2p1(const T u) { return u ? static_cast<T>(64 - __builtin_clzll(static_cast<u64>(u))) : static_cast<T>(0); }
template<typename T> constexpr T msbp1(const T u) { return log2p1(u); }
template<typename T> constexpr T lsbp1(const T u) { return __builtin_ffsll(u); }
template<typename T> constexpr T clog(const T u) { return u ? log2p1(u - 1) : static_cast<T>(u); }
template<typename T> constexpr bool ispow2(const T u) { return u and (static_cast<u64>(u) & static_cast<u64>(u - 1)) == 0; }
template<typename T> constexpr T ceil2(const T u) { return static_cast<T>(1) << clog(u); }
template<typename T> constexpr T floor2(const T u) { return u == 0 ? static_cast<T>(0) : static_cast<T>(1) << (log2p1(u) - 1); }
template<typename T> constexpr bool btest(const T mask, const usize ind) { return static_cast<bool>((static_cast<u64>(mask) >> ind) & static_cast<u64>(1)); }
template<typename T> void bset(T& mask, const usize ind) { mask |= (static_cast<T>(1) << ind); }
template<typename T> void breset(T& mask, const usize ind) { mask &= ~(static_cast<T>(1) << ind); }
template<typename T> void bflip(T& mask, const usize ind) { mask ^= (static_cast<T>(1) << ind); }
template<typename T> void bset(T& mask, const usize ind, const bool b) { (b ? bset(mask, ind) : breset(mask, ind)); }
template<typename T> constexpr T bcut(const T mask, const usize ind) { return ind == 0 ? static_cast<T>(0) : static_cast<T>((static_cast<u64>(mask) << (64 - ind)) >> (64 - ind)); }
template<typename T> bool chmin(T& a, const T& b) { return (a > b ? a = b, true : false); }
template<typename T> bool chmax(T& a, const T& b) { return (a < b ? a = b, true : false); }
constexpr unsigned int mod                  = 1000000007;
template<typename T> constexpr T inf_v      = std::numeric_limits<T>::max() / 4;
template<typename Real> constexpr Real pi_v = Real{3.141592653589793238462643383279502884};
auto mfp = [](auto&& f) { return [=](auto&&... args) { return f(f, std::forward<decltype(args)>(args)...); }; };

template<typename T>
T in()
{
    T v;
    return std::cin >> v, v;
}
template<typename T, typename Uint, usize n, usize i>
T in_v(typename std::enable_if<(i == n), c_arr<Uint, n>>::type) { return in<T>(); }
template<typename T, typename Uint, usize n, usize i>
auto in_v(typename std::enable_if<(i < n), c_arr<Uint, n>>::type& szs)
{
    const usize s = (usize)szs[i];
    std::vector<decltype(in_v<T, Uint, n, i + 1>(szs))> ans(s);
    for (usize j = 0; j < s; j++) { ans[j] = in_v<T, Uint, n, i + 1>(szs); }
    return ans;
}
template<typename T, typename Uint, usize n>
auto in_v(c_arr<Uint, n> szs) { return in_v<T, Uint, n, 0>(szs); }
template<typename... Types>
auto in_t() { return std::tuple<std::decay_t<Types>...>{in<Types>()...}; }
struct io_init
{
    io_init()
    {
        std::cin.tie(nullptr), std::ios::sync_with_stdio(false);
        std::cout << std::fixed << std::setprecision(20);
    }
    void clear()
    {
        std::cin.tie(), std::ios::sync_with_stdio(true);
    }
} io_setting;

int out() { return 0; }
template<typename T>
int out(const T& v) { return std::cout << v, 0; }
template<typename T>
int out(const std::vector<T>& v)
{
    for (usize i = 0; i < v.size(); i++) {
        if (i > 0) { std::cout << ' '; }
        out(v[i]);
    }
    return 0;
}
template<typename T1, typename T2>
int out(const std::pair<T1, T2>& v) { return out(v.first), std::cout << ' ', out(v.second), 0; }
template<typename T, typename... Args>
int out(const T& v, const Args... args) { return out(v), std::cout << ' ', out(args...), 0; }
template<typename... Args>
int outln(const Args... args) { return out(args...), std::cout << '\n', 0; }
template<typename... Args>
int outel(const Args... args) { return out(args...), std::cout << std::endl, 0; }
#    define SHOW(...) static_cast<void>(0)
constexpr ull TEN(const usize n) { return n == 0 ? 1ULL : TEN(n - 1) * 10ULL; }

template<typename T, typename Uint, usize n, usize i>
auto make_v(typename std::enable_if<(i == n), c_arr<Uint, n>>::type, const T& v = T{}) { return v; }
template<typename T, typename Uint, usize n, usize i>
auto make_v(typename std::enable_if<(i < n), c_arr<Uint, n>>::type szs, const T& v = T{})
{
    const usize s = (usize)szs[i];
    return std::vector<decltype(make_v<T, Uint, n, i + 1>(szs, v))>(s, make_v<T, Uint, n, i + 1>(szs, v));
}
template<typename T, typename Uint, usize n>
auto make_v(c_arr<Uint, n> szs, const T& t = T{}) { return make_v<T, Uint, n, 0>(szs, t); }

template<typename Cost = usize>
struct edge
{
    using cost_type = Cost;
    usize u, v;
    Cost c;
    edge(const usize u, const usize v) : u{u}, v{v}, c{1} {}
    edge(const usize u, const usize v, const Cost& c) : u{u}, v{v}, c{c} {}
    operator usize() const { return v; }
    usize from() const { return u; }
    usize to() const { return v; }
    Cost cost() const { return c; }
    friend std::ostream& operator<<(std::ostream& os, const edge& e) { return os << e.u << "->" << e.v << ":" << e.c; }
};
template<typename Edge>
class base_graph
{
public:
    base_graph(const usize n) : v{n}, es(n), res(n) {}
    void add_edge(const usize u, const usize v, const bool bi = false)
    {
        es[u].emplace_back(u, v), res[v].emplace_back(v, u);
        if (bi) { es[v].emplace_back(v, u), res[u].emplace_back(u, v); }
    }
    template<typename Cost>
    void add_edge(const usize u, const usize v, const Cost& c, const bool bi = false)
    {
        es[u].emplace_back(u, v, c), res[v].emplace_back(v, u, c);
        if (bi) { es[v].emplace_back(v, u, c), res[u].emplace_back(u, v, c); }
    }
    std::vector<Edge>& operator[](const usize u) { return es[u]; }
    const std::vector<Edge>& operator[](const usize u) const { return es[u]; }
    std::vector<Edge>& from(const usize u) { return es[u]; }
    const std::vector<Edge>& from(const usize u) const { return es[u]; }
    std::vector<Edge>& to(const usize v) { return res[v]; }
    const std::vector<Edge>& to(const usize v) const { return res[v]; }
    usize size() const { return v; }
    friend std::ostream& operator<<(std::ostream& os, const base_graph& g)
    {
        for (usize i = 0; i < g.v; i++) {
            for (const auto& e : g.es[i]) { os << e << '\n'; }
        }
        return os;
    }

private:
    usize v;
    std::vector<std::vector<Edge>> es, res;
};
template<typename Edge>
using base_tree = base_graph<Edge>;
using graph     = base_graph<edge<>>;
using tree      = base_graph<edge<>>;
template<typename Cost>
using cost_graph = base_graph<edge<Cost>>;
template<typename Cost>
using cost_tree = base_graph<edge<Cost>>;
int main()
{
    while (true) {
        const auto N  = in<int>();
        const auto M  = in<int>();
        const auto S1 = in<int>() - 1;
        const auto S2 = in<int>() - 1;
        const auto T  = in<int>() - 1;
        if (N == 0) { break; }
        cost_graph<ll> g(N);
        for (int i = 0; i < M; i++) {
            const auto a = in<int>() - 1, b = in<int>() - 1;
            const auto ws = in<std::string>();
            g.add_edge(a, b, ws == "x" ? -1LL : std::stoll(ws), true);
        }
        auto dijk = [&](const int s) {
            using pii = std::pair<int, int>;
            using plp = std::pair<ll, pii>;
            min_heap<plp> Q;
            auto dss  = make_v<ll>({N, 101}, inf_v<ll>);
            dss[s][0] = 0;
            Q.push({0, {s, 0}});
            while (not Q.empty()) {
                const auto p = Q.top();
                Q.pop();
                const auto d = p.first;
                const int v  = p.second.first;
                const int bn = p.second.second;
                if (dss[v][bn] < d) { continue; }
                for (const auto& e : g[v]) {
                    const int to  = e.to();
                    const ll cost = e.cost();
                    if (cost == -1LL) {
                        const int nbn = bn + 1;
                        if (nbn > 100) { continue; }
                        const ll nd = dss[v][bn];
                        if (dss[to][nbn] <= nd) { continue; }
                        dss[to][nbn] = nd, Q.push({nd, {to, nbn}});
                    } else {
                        const int nbn = bn;
                        const ll nd   = dss[v][bn] + cost;
                        if (dss[to][nbn] <= nd) { continue; }
                        dss[to][nbn] = nd, Q.push({nd, {to, nbn}});
                    }
                }
            }
            return dss[T];
        };
        const auto d1s = dijk(S1);
        const auto d2s = dijk(S2);
        SHOW(d1s, d2s);
        using seg = std::pair<ll, ll>;
        auto segs = [&](const auto& ds) {
            std::vector<seg> ss(101, {-1, -1});
            for (int i = 0; i <= 100; i++) {
                if (ds[i] == inf_v<ll>) { continue; }
                ll inf = 0LL, sup = inf_v<ll>;
                for (int j = 0; j <= 100; j++) {
                    if (i == j) { continue; }
                    if (ds[j] == inf_v<ll>) { continue; }
                    if (j > i) {
                        const ll x = (ds[i] - ds[j] + j - i - 1) / (ll)(j - i);
                        chmax(inf, x);
                    } else {
                        const ll x = (ds[j] - ds[i]) / (ll)(i - j);
                        chmin(sup, x);
                    }
                }
                ss[i] = {inf, sup};
            }
            return ss;
        };
        const auto s1s = segs(d1s);
        const auto s2s = segs(d2s);
        ll ans         = inf_v<ll>;
        auto f         = [&](const ll a, const ll b, const ll x) { return a * x + b; };
        for (int i = 0; i <= 100; i++) {
            const ll bi = d1s[i];
            const ll ai = i;
            for (int j = 0; j <= 100; j++) {
                if (d1s[i] == inf_v<ll>) { continue; }
                if (d2s[j] == inf_v<ll>) { continue; }
                ll xl = s1s[i].first, xr = s1s[i].second;
                chmax(xl, s2s[j].first), chmin(xr, s2s[j].second);
                if (xl > xr) { continue; }
                const ll bj = d2s[j];
                const ll aj = j;
                auto g      = [&](const ll x) { return f(ai, bi, x) - f(aj, bj, x); };
                const ll lo = g(xl);
                const ll ro = g(xr);
                if ((lo >= 0) ^ (ro >= 0)) {
                    const ll x1 = xl + std::abs(lo) / std::abs(i - j);
                    const ll x2 = x1 + 1;
                    chmin(ans, std::min(std::abs(g(x1)), std::abs(g(x2))));
                } else {
                    chmin(ans, std::min(std::abs(lo), std::abs(ro)));
                }
            }
        }
        outln(ans);
    }
    return 0;
}



Measured memory_bytes: 6032