#include <bits/stdc++.h> using namespace std; const int maxn = 1e4 + 5; int n, ans, dp[maxn]; vector<int>edge[maxn]; inline int read(){ int s = 0, w = 1; char ch = getchar(); while(ch < '0' || ch > '9'){ if(ch == '-') w = -1; ch = getchar();} while(ch >= '0' && ch <= '9') s = s * 10 + ch - '0', ch = getchar(); return s * w; } inline void print(int x){ if(x < 0) x = ~x + 1, putchar('-'); if(x > 9) print(x / 10); putchar(x % 10 + '0'); } void dfs(int u, int f){ dp[u] = 0; for(auto v : edge[u]){ if(v == f) continue; dfs(v, u); ans = max(ans, dp[u] + dp[v] + 1); dp[u] = max(dp[u], dp[v] + 1); } } int main(){ n = read(); for(int i = 1; i < n; i++){ int u = read(), v = read(); edge[u].push_back(v); edge[v].push_back(u); } dfs(1, 0); print(ans); return 0; }