#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <vector>
typedef long long llong;
const int MAXN = 2500 + 10;
const int INF = 1e9;
int n;
int l[MAXN];
int r[MAXN];
int dp[MAXN][MAXN];
bool bl[MAXN][MAXN];
int from;
int f(int left, int right)
{
if (left == 1 && right == n)
{
return 0;
}
if (bl[left][right])
{
return dp[left][right];
}
bl[left][right] = true;
dp[left][right] = INF;
for (int i = left ; i <= right ; ++i)
{
if (l[i] < left)
{
dp[left][right] = std::min(dp[left][right], f(l[i], std::max(r[i], right)) + 1);
}
if (r[i] > right)
{
dp[left][right] = std::min(dp[left][right], f(std::min(l[i], left), r[i]) + 1);
}
}
return dp[left][right];
}
void solve()
{
std::cout << f(from, from) << '\n';
}
void input()
{
std::cin >> n;
for (int i = 1 ; i <= n ; ++i)
{
std::cin >> l[i] >> r[i];
}
std::cin >> from >> from;
}
void fastIOI()
{
std::ios_base :: sync_with_stdio(0);
std::cout.tie(nullptr);
std::cin.tie(nullptr);
}
int main()
{
fastIOI();
input();
solve();
return 0;
}
