FOXLINGS.cpp

#include<bits/stdc++.h>
using namespace std;
using lld=long long int;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n,m;
    cin>>n>>m;
    int arr[n+1];
    memset(arr,-1,sizeof(arr));
    while(m--)
    {
        int val,res1,res2,par1,par2,a,b,ptr;
        cin>>a>>b;

        val=a;
        while(arr[val]>0)
        val=arr[val];
        par1=val;
        res1=arr[val];
        val=b;
        while(arr[val]>0)
        val=arr[val];
        res2=arr[val];
        par2=val;

        if(par1!=par2)
        {
            if(res1<=res2)
            {
                arr[par2]=par1;
                arr[par1]=res1+res2;
                val=b;
                while(arr[val]!=par1)
                {
                val=arr[b];
                arr[b]=par1;
                b=val;
                }
            }
            else
            {
                arr[par1]=par2;
                arr[par2]=res1+res2;
                val=a;
                while(arr[val]!=par2)
                {
                val=arr[a];
                arr[a]=par2;
                a=val;
                }
            }
        }
    }
    int cnt=0;
    for(int i=1;i<=n;i++)
    if(arr[i]<0)
    cnt++;
    cout<<cnt;
}