Hackerearth Unreachable Nodes

Problem Link: Unreachable Nodes

/*
Lionel Messi is such a player that you may catch him, you may touch him, you may feel him
and definitely you may Love him.
Lionel Messi is Messi. A little Magician in this World.

*/

// Accepted

#include<bits/stdc++.h>

using namespace std;

#define fast ios_base::sync_with_stdio(0)
#define bfast cin.tie(0)
#define outs(x) cout << x << " "
#define outn(x) cout << x << "\n"
#define sf scanf
#define pf printf
#define nl puts("")
#define psb push_back
#define loop0(n) for(int i=0; i<n; i++)
#define loop1(n) for(int i=1; i<=n; i++)
#define mpair(x , y) make_pair(x , y)
#define all(x) x.begin(), x.end()
#define pi acos(-1.0)
#define psb push_back

typedef unsigned long long ull;
typedef long long LL;
typedef vector<int>vii;
typedef vector<LL>vll;
typedef vector<string>vs;
typedef map<int, int>mpii;
typedef map<string, int>mpsi;
typedef map<char, int>mpci;
typedef map<LL, LL>mpll;

const int mod = 1000007;
const int high = 100003;


struct printf
{
    void ek(int n){cout << n << "\n";}
    void dui(int x , int y) { cout << x << " " << y << "\n"; }
    void tin(int x , int y , int z) { cout << x << " " << y << " " << z << "\n"; }
}tp;

struct sieve
{
    int prm[high], plen=0;
    bitset<high>bs;
    void get_prime()
    {
        LL i , j;
        bs.set();
        bs[0]=bs[1]=0;
        for(i=2; i<=high; i++)
        {
            if(bs[i])
            {
                prm[plen++] = i;

                for(j=i*i; j<=high; j+=i) bs[j] = 0;
            }
        }
    }
    void pprm(){ for(int i=0; i<100; i++) cout << prm[i] << "; "; }
}prime;

vii adj[high];
bool visited[high];

void dfs(int s)
{
    visited[s] = true;

    int i=0;

    for(i=0; i<adj[s].size(); i++)
    {
        if(!visited[adj[s][i]])
        {
            visited[adj[s][i]] = true;

            dfs(adj[s][i]);
        }
    }
}

int main()
{
    fast;
    int n , i , m , x , a , b , cnt=0;
    while(cin >> n >> m)
    {
        memset(visited , false , sizeof visited);

        for(i=0; i<m; i++)
        {
            cin >> a >> b;
            adj[a].psb(b);
            adj[b].psb(a);
        }

        cin >> x;

        dfs(x);

        cnt=0;

        for(i=1; i<=n; i++)
        {
            if(!visited[i]) cnt++;
        }

        outn(cnt);
    }

    return 0;
}