PT07Z.cpp

// Ivan Carvalho
// Solution to https://www.spoj.com/problems/PT07Z/
#include <cstdio>
#include <vector>
#define MAXN 10010
using namespace std;
int maior, aux, n;
vector<int> grafo[MAXN];
void dfs(int x, int p, int dist) {
    if (dist > maior) {
        maior = dist;
        aux = x;
    }
    for (int i = 0; i < grafo[x].size(); i++) {
        int v = grafo[x][i];
        if (v != p) {
            dfs(v, x, dist + 1);
        }
    }
}
int main() {
    scanf("%d", &n);
    for (int i = 1; i < n; i++) {
        int u, v;
        scanf("%d %d", &u, &v);
        grafo[u].push_back(v);
        grafo[v].push_back(u);
    }
    dfs(1, -1, 0);
    maior = 0;
    dfs(aux, -1, 0);
    printf("%d\n", maior);
    return 0;
}