#include <cstdio>
#include <cstring>
#include <vector>
using namespace std;
#define NMAX 100005
int n, maxi, far;
vector<int> a[NMAX];
bool viz[NMAX];

void DFS(int nod, int cost){
    viz[nod] = true;
    if(cost > maxi){
        far = nod;
        maxi = cost;
    }
    int i;
    for(i=0; i<a[nod].size(); i++){
        if(!viz[ a[nod][i] ])
            DFS(a[nod][i], cost + 1);
    }
}

int main(){

    FILE *fin, *fout;
    fin = fopen("darb.in", "r");
    fout = fopen("darb.out", "w");

    int i, x, y;
    fscanf(fin, "%d", &n);
    for(i=1; i<=n - 1; i++){
        fscanf(fin, "%d%d", &x, &y);
        a[x].push_back(y);
        a[y].push_back(x);
    }

    DFS(1, 1);
    memset(viz, false, sizeof(viz));
    DFS(far, 1);

    fprintf(fout, "%d", maxi);

    fclose(fin);
    fclose(fout);
    return 0;
}