Connect the graph

#include <iostream>
#include <vector>


using namespace std;
int visited[100010];

vector <int> g[100010];
int name[1000010];
void dfs(int x)
{
    if(visited[x])
    {
        return ;
    }
    visited[x]=true;
    for(auto c : g[x])
    {
        if(!visited[c])
        {
            dfs(c);
        }
    }
}
int main()
{
    int n, m;
    cin >> n >> m;
    int u,v;
    for(int i=0; i<m; ++i)
    {
        cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    int cnt=0;

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

            dfs(i);
            ++cnt;
            name[cnt]=i;
        }
    }

    int k=cnt-1;
    cout << k << "\n";
    for(int i=1; i<=k; ++i)
    {
        cout << name[i] << " " << name[i+1] << "\n";
    }


    return 0;
}