```cpp
#include <bits/stdc++.h>
#define int long long
using namespace std;
const int MAXN = 1005;
int n, m, ans;
bool visited[MAXN];
vector<int> graph[MAXN];
void bfs(int p) {
queue<pair<int, int>> q;
q.emplace(make_pair(p, 0));
while (!q.empty()) {
int now_p = q.front().first, dis = q.front().second;
q.pop();
if (visited[now_p]) { break; }
else { visited[now_p] = true; }
ans = max(ans, dis);
for (auto e : graph[now_p]) {
if (visited[e]) { continue; }
q.emplace(make_pair(e, dis + 1));
}
}
}
signed main() {
while (cin >> n >> m && n + m) {
ans = 0;
for (int i = 1; i <= n; i ++) { graph[i].clear(); }
for (int i = 1; i <= m; i ++) {
int a, b;
cin >> a >> b;
graph[a].emplace_back(b);
graph[b].emplace_back(a);
}
for (int i = 1; i <= n; i ++) {
memset(visited, false, sizeof(visited));
bfs(i);
}
cout << ans * 100 << endl;
}
return 0;
}
```
by kncjjdr05 @ 2023-01-23 12:51:41