#include <iostream>
#include<fstream>
#include<vector>
#include<set>
#include<bitset>
#include<queue>
using namespace std;
const int NMAX=450001;

ifstream fin("santa.in");
ofstream fout("santa.out");

struct muchie
{
    int x,y;
    muchie(int xx=0,int yy=0)
    {
        x=xx,y=yy;
    }
};

int p,n,m,nrfii,nrcb,st,e,q,nrs,nrm,nrq,elem1,elem2,
    niv[NMAX],nma[NMAX],
    s[NMAX],vf,v[NMAX];

vector<int>g[NMAX],cb[NMAX];
vector<muchie>mc;
set<int>pa;
bitset<NMAX>viz;

void citire()
{
    fin>>n>>m;
    for(int i=1; i<=m; i++)
    {
        int x,y;
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    fin>>st>>e>>q;
}

void dfscb(int x,int tata)
{
    s[++vf]=x;
    viz[x]=1;
    niv[x]=niv[tata]+1;
    nma[x]=niv[x];
    for(const auto &y:g[x])
    {
        if(y==tata) continue;
        if(viz[y])
            nma[x]=min(nma[x],niv[y]);
        else
        {
            dfscb(y,x);
            nma[x]=min(nma[x],nma[y]);
            if(niv[x]<=nma[y])
            {
                nrcb++;
                if(st==x||st==y) nrs=nrcb;
                if(e==x||e==y) nrm=nrcb;
                if(q==x||q==y) nrq=nrcb;
                while(s[vf]!=y)
                {
                    if(s[vf-1]==st ) nrs=nrcb;
                    if(s[vf-1]==e) nrm=nrcb;
                    if(s[vf-1]==q) nrq=nrcb;
                    cb[nrcb].push_back(s[vf--]);
                }
                cb[nrcb].push_back(y);
                --vf;
                cb[nrcb].push_back(x);
            }
        }
    }
}

void dfspa(int x,int tata)
{
    viz[x]=1;
    niv[x]=niv[tata]+1;
    nma[x]=niv[x];
    for(const auto &y:g[x])
    {
        if(y==tata) continue;
        if(viz[y])
            nma[x]=min(nma[x],niv[y]);
        else
        {
            dfspa(y,x);
            nma[x]=min(nma[x],nma[y]);
            if(x==1)
                nrfii++;
            else
            {
                if(niv[x]<=nma[y])
                    pa.insert(x);
            }
        }
    }
}


void bfs(int nod)
{
    queue<int>q;
    v[nod]=1;
    q.push(nod);
    while(!q.empty())
    {
        int crt=q.front();
        q.pop();
        for(const auto &i:g[crt])
            if(v[i]==0)
            {
                q.push(i);
                v[i]=v[crt]+1;
            }
    }
}

int main()
{
    citire();
    dfscb(1,0);
    for(int i=1; i<=n; i++)
        viz[i]=0;
    dfspa(1,0);
    if(nrfii>=2) pa.insert(1);

    bfs(q);

    if(nrs==nrm)
    {
        if(nrs==nrq)
            fout<<cb[nrs].size()-1;
        else
        {
            for(const auto &x:cb[nrs])
                if(pa.find(x)!=pa.end())
                {
                    elem1=x;
                    break;
                }
            fout<<v[elem1]+cb[nrs].size()-2;
        }

    }
    else
    {
        if(nrs==nrq||nrq==nrm)
            fout<<cb[nrs].size()+cb[nrm].size()-2;
        else
        {

            for(const auto &x:cb[nrm])
                if(pa.find(x)!=pa.end())
                {
                    elem1=x;
                    break;
                }
            for(const auto &x:cb[nrs])
                if(pa.find(x)!=pa.end())
                {
                    elem2=x;
                    break;
                }
            if(elem1==e&&elem2==st)
                fout<<"No chance";
                else
            fout<<min(v[elem1],v[elem2])+cb[nrm].size()+cb[nrs].size()-3;
        }
    }

    fin.close();
    fout.close();
    return 0;
}