#include <stdio.h>

typedef struct List {
	struct List *next;
	int v;
} list;

void chmax(int* a, int b)
{
	if (*a < b) *a = b;
}

int main()
{
	int i, N, u, w;
	list *adj[100001] = {}, e[200001], *p;
	scanf("%d", &N);
	for (i = 0; i < N - 1; i++) {
		scanf("%d %d", &u, &w);
		e[i*2].v = w;
		e[i*2+1].v = u;
		e[i*2].next = adj[u];
		e[i*2+1].next = adj[w];
		adj[u] = &(e[i*2]);
		adj[w] = &(e[i*2+1]);
	}
	
	int par[100001] = {}, q[100001], head, tail;
	par[1] = 1;
	q[0] = 1;
	for (head = 0, tail = 1; head < tail; head++) {
		u = q[head];
		for (p = adj[u]; p != NULL; p = p->next) {
			w = p->v;
			if (par[w] == 0) {
				par[w] = u;
				q[tail++] = w;
			}
		}
	}
	
	int dp[2][100001] = {}, tmp[2];
	for (head--; head > 0; head--) {
		u = q[head];
		tmp[0] = 0;
		tmp[1] = 0;
		chmax(&(tmp[0]), dp[0][par[u]] + dp[0][u]);
		chmax(&(tmp[0]), dp[0][par[u]] + dp[1][u]);
		chmax(&(tmp[1]), dp[1][par[u]] + dp[0][u]);
		chmax(&(tmp[1]), dp[1][par[u]] + dp[1][u]);
		chmax(&(tmp[1]), dp[0][par[u]] + dp[0][u] + 1);
		dp[0][par[u]] = tmp[0];
		dp[1][par[u]] = tmp[1];
	}
	printf("%d\n", (dp[0][1] > dp[1][1])? dp[0][1]: dp[1][1]);
	fflush(stdout);
	return 0;
}