#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<ll, ll> ii;
typedef vector<ii> vii;

ll n, m, f, t, s; 
vector<vll> e;

int main() {
cin.tie(0)->sync_with_stdio(0);
cin.exceptions(cin.failbit);

cin >> n>>m>>f>>t>>s;
e = vector<vll> (n);

rep(i, 0, m)
{
    ll x, y; cin >> x >> y;
    e[y].push_back(x);
    e[x].push_back(y);

}

queue<ii> qT;
vector<vector<ll>> tDistance(n, vll(2, -1));
qT.push({t, 0});
tDistance[t][0] = 0;

while(!qT.empty())
{
    auto cur = qT.front(); qT.pop();
    ll nextParity = (cur.second + 1 )%2;
    for(auto neigh : e[cur.first])
    {
        if(tDistance[neigh][nextParity] != -1) continue;

        tDistance[neigh][nextParity] = cur.second +1;
        qT.push({neigh, cur.second +1});
    }
}



vector<vector<ll>> sDistance(n, vll(2, -1));
queue<ii> qS;
qS.push({s, 0});
sDistance[s][0]= 0;

while(!qS.empty())
{
    auto cur = qS.front(); qS.pop();
    if(cur.first == f)
    {
        cout << cur.second << endl;
        return 0;
    }

    ll nextParity = (cur.second + 1 )%2;
    for(auto neigh : e[cur.first])
    {
        if(sDistance[neigh][nextParity] != -1) continue;

        if(tDistance[neigh][nextParity] != -1 && tDistance[neigh][nextParity] <= cur.second + 1) continue;

        sDistance[neigh][nextParity] = cur.second + 1;
        qS.push({neigh, cur.second +1});
    }

    {
        if(sDistance[cur.first][nextParity] != -1)
        continue;
        if(tDistance[cur.first][nextParity] != -1 &&
            tDistance[cur.first][nextParity] <= cur.second+1)
            continue;

        sDistance[cur.first][nextParity] = cur.second + 1;
        qS.push({cur.first, cur.second +1});

    }
    
}
    cout << "death" << endl;

}