#include <cstdio>
#include <vector>

using namespace std;

#define DIM 100005

int N, x, y, dp[DIM], Passed[DIM], pos;
vector <vector <int> > Nod;

void Parcurgere(int x);

int main() {
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);

    scanf("%d\n", &N);

    Nod.resize(N + 1);

    for(int i = 1; i <= N; ++i) {
        scanf("%d %d\n", &x, &y);

        Nod[x].push_back(y);
        Nod[y].push_back(x);
    }

    for(int i = 1; i <= N; ++i) {
        dp[i] = 0;
        Passed[i] = 0;
    }

    int mx = 0;

    for(int i = 1; i <= N; ++i) {
        dp[i] = 0;
        Passed[i] = 0;
    }

    Parcurgere(1);

    for(int i = 2; i <= N; ++i) {
        if(mx < dp[i]) {
            mx = dp[i],
            pos = i;
        }
    }

    for(int i = 1; i <= N; ++i) {
        dp[i] = 0;
        Passed[i] = 0;
    }

    Parcurgere(pos);

    for(int i = 1; i <= N; ++i) {
        if(mx < dp[i]) {
            mx = dp[i];
        }
    }

    printf("%d\n", mx + 1);

    return 0;
}

void Parcurgere(int x) {
    Passed[x] = 1;
    for(auto y: Nod[x]) {
        if(!Passed[y]) {
            dp[y] = dp[x] + 1;
            Parcurgere(y);
        }
    }
}