#include <cstdio>
#include <vector>

using namespace std;

vector<int> v[100010];
int viz[100010],n,m,x,y,i;
void dfs(int);

int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);

    scanf("%d%d",&n,&m);

    for(;m;m--)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }

    for(i=1;i<=n;i++)
        if(!viz[i])
        {
            m++;
            dfs(i);
        }

    printf("%d\n",m);

    return 0;
}

void dfs(int nod)
{
    viz[nod] = 1;
    for(auto vec:v[nod])
        if(!viz[vec])
            dfs(vec);
}