#include<bits/stdc++.h>
#define endl '\n'
#define pb push_back
using namespace std;
const int maxn = 3e3 + 10;
void speed()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}
int n, q;
int lt[maxn], rt[maxn];
int dp[maxn][maxn];
int main()
{
speed();
cin >> n;
for (int i = 1; i <= n; ++ i)
{
cin >> lt[i] >> rt[i];
}
cin >> q;
int x;
cin >> x;
for (int i = 1; i <= n; ++ i)
{
for (int j = 1; j <= n; ++ j)
dp[i][j] = 1e9;
}
dp[lt[x]][rt[x]] = 1;
for (int sz = 1; sz <= n; ++ sz)
{
for (int i = 1; i <= n; ++ i)
{
int j = i + sz - 1;
if(j > n)break;
if(dp[i][j] == 1e9)continue;
//cout << i << " " << j << " is " << dp[i][j] << endl;
for (int k = 1; k <= n; ++ k)
{
if(k >= i && k <= j)
{
int newl = min(i, lt[k]);
int newr = max(j, rt[k]);
dp[newl][newr] = min(dp[i][j] + 1, dp[newl][newr]);
}
}
}
}
if(dp[1][n] == 1e9)cout << -1 << endl;
else cout << dp[1][n] << endl;
return 0;
}
