#include<bits/stdc++.h>
#define M 50005
using namespace std;
using ull = unsigned long long;
int n, ans[M];
ull hp[M][800];
void add(int x, int y)
{
	for(int i = 0; i <= n / 63; i++)
	{
		hp[y][i] += (hp[x][i] >> 1);
		if(hp[x][i + 1] & 1) hp[y][i] += (1ull << 62);
		if(hp[y][i] >> 63) hp[y][i + 1]++, hp[y][i] ^= (1ull << 63);
	}
}
int ctz(int i)
{
	for(int j = 0; j <= n / 63; j++) if(hp[i][j]) return j * 63 + __builtin_ctzll(hp[i][j]);
}
int main()
{
	scanf("%d", &n);
	hp[1][n / 63] = 1ull << (n % 63);
	int minn = n;
	for(int i = 1, x; i <= n; i++)
	{
		scanf("%d", &x), add(i, x);
		scanf("%d", &x), add(i, x);
		minn = min(minn, ctz(i));
	}
	int pw = n - minn + 1;
	ans[0] = 1;
	int tot = 1;
	while(pw)
	{
		int nt = min(pw, 25);
		pw -= nt;
		for(int i = 0; i < tot; i++) ans[i] <<= nt;
		for(int i = 0; i < tot; i++) ans[i + 1] += ans[i] / 10, ans[i] %= 10;
		while(ans[tot]) ans[tot + 1] += ans[tot] / 10, ans[tot] %= 10, tot++;
	}
	for(int i = tot - 1; i >= 0; i--) printf("%d", ans[i]);
	return 0;
}