#include <fstream>
#include <stack>
#include <vector>
using namespace std;

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

const int MAX_N = 100010;

vector<int> graf[MAX_N];
stack<int> st;
bool visited[MAX_N];

int N, M;

int dfs(int node);

int main(int argc, char const *argv[])
{
    fin >> N >> M;
    for (int i = 0; i < M; ++i) {
        int x, y;
        fin >> x >> y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }

    int result = 0;
    for (int i = 1; i <= N; ++i) {
        while (visited[i] == true) ++i;
        if (i > N) break;
        visited[i] = true;
        int d = dfs(i);
        result = d > result ? d : result;
    }
    fout << result;

    return 0;
}

int dfs(int node) {
    int gs = 0;
    st.push(node);
    while (!st.empty()) {
        int t = st.top();
        st.pop();
        ++gs;
        for (int i = 0; i < graf[t].size(); ++i) {
            if (!visited[graf[t][i]]) {
                st.push(graf[t][i]);
                visited[st.top()] = true;
            }
        }
    }
    return gs;
}