// 嘘ヒューリスティック
// x-y, y-z, z-x のうち一つを固定して残り二つの長さの和を MCF で最小化するのを反復する山登り
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <deque>
#include <forward_list>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using lint = long long;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template <typename T, typename V>
void ndarray(vector<T>& vec, const V& val, int len) { vec.assign(len, val); }
template <typename T, typename V, typename... Args> void ndarray(vector<T>& vec, const V& val, int len, Args... args) { vec.resize(len), for_each(begin(vec), end(vec), [&](T& v) { ndarray(v, val, args...); }); }
template <typename T> bool chmax(T &m, const T q) { return m < q ? (m = q, true) : false; }
template <typename T> bool chmin(T &m, const T q) { return m > q ? (m = q, true) : false; }
int floor_lg(long long x) { return x <= 0 ? -1 : 63 - __builtin_clzll(x); }
template <typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l.second + r.second); }
template <typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l.second - r.second); }
template <typename T> vector<T> sort_unique(vector<T> vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; }
template <typename T> int arglb(const std::vector<T> &v, const T &x) { return std::distance(v.begin(), std::lower_bound(v.begin(), v.end(), x)); }
template <typename T> int argub(const std::vector<T> &v, const T &x) { return std::distance(v.begin(), std::upper_bound(v.begin(), v.end(), x)); }
template <typename T> istream &operator>>(istream &is, vector<T> &vec) { for (auto &v : vec) is >> v; return is; }
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <typename T, size_t sz> ostream &operator<<(ostream &os, const array<T, sz> &arr) { os << '['; for (auto v : arr) os << v << ','; os << ']'; return os; }
#if __cplusplus >= 201703L
template <typename... T> istream &operator>>(istream &is, tuple<T...> &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return is; }
template <typename... T> ostream &operator<<(ostream &os, const tuple<T...> &tpl) { os << '('; std::apply([&os](auto &&... args) { ((os << args << ','), ...);}, tpl); return os << ')'; }
#endif
template <typename T> ostream &operator<<(ostream &os, const deque<T> &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <typename T> ostream &operator<<(ostream &os, const set<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T, typename TH> ostream &operator<<(ostream &os, const unordered_set<T, TH> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa) { os << '(' << pa.first << ',' << pa.second << ')'; return os; }
template <typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
template <typename TK, typename TV, typename TH> ostream &operator<<(ostream &os, const unordered_map<TK, TV, TH> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; }
#ifdef HITONANODE_LOCAL
const string COLOR_RESET = "\033[0m", BRIGHT_GREEN = "\033[1;32m", BRIGHT_RED = "\033[1;31m", BRIGHT_CYAN = "\033[1;36m", NORMAL_CROSSED = "\033[0;9;37m", RED_BACKGROUND = "\033[1;41m", NORMAL_FAINT = "\033[0;2m";
#define dbg(x) cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << endl
#define dbgif(cond, x) ((cond) ? cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << endl : cerr)
#else
#define dbg(x) (x)
#define dbgif(cond, x) 0
#endif

#include <atcoder/mincostflow>

uint32_t rand_int() // XorShift random integer generator
{
    static uint32_t x = 123456789, y = 362436069, z = 521288629, w = 88675123;
    uint32_t t = x ^ (x << 11);
    x = y;
    y = z;
    z = w;
    return w = (w ^ (w >> 19)) ^ (t ^ (t >> 8));
}

int N;
int x, y, z;
vector<vector<int>> to;

struct State {
    vector<int> xy;
    vector<int> yz;
    vector<int> zx;
    int n_feasible() const { return (!xy.empty()) + (!yz.empty()) + (!zx.empty()); }
    bool feasible() const { return xy.size() and yz.size() and zx.size(); }
    int length() const {
        if (!feasible()) return -1;
        return xy.size() + yz.size() + zx.size() - 3;
    }
    vector<int> render() const {
        if (!feasible()) return {};
        vector<int> ret = xy;
        ret.pop_back();
        ret.insert(ret.end(), yz.begin(), yz.end());
        ret.pop_back();
        ret.insert(ret.end(), zx.begin(), zx.end());
        return ret;
    }
};

pair<vector<int>, vector<int>> twopaths(const State &state, int from, int to1, int to2) {
    const int gt = N * 2;
    atcoder::mcf_graph<int, int> graph(gt + 1);

    vector<int> valid_v(N, 1);
    for (auto i : state.xy) valid_v[i] = 0;
    for (auto i : state.yz) valid_v[i] = 0;
    for (auto i : state.zx) valid_v[i] = 0;

    // REP(i, N) {
    //     if (rand_int() % 100 == 0) valid_v[i] = 0;
    // }
    for (int i = 0; i < N; ++i) {
        graph.add_edge(i, i + N, valid_v[i], 0);
    }

    for (int i = 0; i < N; ++i) {
        for (auto j : to[i]) graph.add_edge(i + N, j, 1, 1);
    }
    graph.add_edge(to1, gt, 1, 0);
    graph.add_edge(to2, gt, 1, 0);
    auto f = graph.flow(from + N, gt, 2);
    if (f.first < 2) return {{}, {}};

    vector<int> conn(N);
    for (auto e : graph.edges()) {
        if (e.flow) {
            if (e.to == gt) continue;
            int s = e.from % N, t = e.to % N;
            conn[s] ^= t;
            conn[t] ^= s;
        }
    }

    vector<int> ret1, ret2;
    while (to1 != from) {
        ret1.push_back(to1);
        to1 = conn[to1];
        conn[to1] ^= ret1.back();
    }
    while (to2 != from) {
        ret2.push_back(to2);
        to2 = conn[to2];
        conn[to2] ^= ret2.back();
    }
    ret1.push_back(from);
    ret2.push_back(from);
    reverse(ret1.begin(), ret1.end());
    reverse(ret2.begin(), ret2.end());
    return {ret1, ret2};
}


void step(State &state) {
    while (state.n_feasible() >= 2) {
        int i = rand_int() % 3;
        if (i == 0) state.xy.clear();
        if (i == 1) state.yz.clear();
        if (i == 2) state.zx.clear();
    }

    for (int t = 0; t < 10; ++t) {
        if (rand_int() % 5 == 0 and state.xy.empty() and state.zx.empty()) {
            auto [xy, xz] = twopaths(state, x, y, z);
            reverse(xz.begin(), xz.end());
            state.xy = xy;
            state.zx = xz;
        }
        if (rand_int() % 5 == 0 and state.xy.empty() and state.yz.empty()) {
            auto [yx, yz] = twopaths(state, y, x, z);
            reverse(yx.begin(), yx.end());
            state.xy = yx;
            state.yz = yz;
        }
        if (rand_int() % 5 == 0 and state.yz.empty() and state.zx.empty()) {
            auto [zx, zy] = twopaths(state, z, x, y);
            reverse(zy.begin(), zy.end());
            state.zx = zx;
            state.yz = zy;
        }
    }
}

int main() {
    int M;
    cin >> N >> M;
    cin >> x >> y >> z;

    --x, --y, --z;
    vector conn(N, vector<int>(N, 1));
    REP(i, N) conn[i][i] = 0;
    while (M--) {
        int a, b;
        cin >> a >> b;
        --a, --b;
        conn[a][b] = conn[b][a] = 0;
    }
    to.assign(N, {});
    REP(i, N) REP(j, N) if (conn[i][j]) to[i].push_back(j);

    State state;
    REP(t, 100) step(state);
    cout << state.length() << '\n';
    // auto path = state.render();
    // for (auto x : path) cout << x << ' ';
    // cout << '\n';
}