// MDSPro
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#include "bits/stdc++.h"
using namespace std;
using ll = long long;
using ld = long double;
const ld PI = 3.141592653589793;
const int MOD = 1e9+7;
const int INF = 1e9;
const ll INFLL = 4e18;
const double EPS = 1e-9;
const int MAXN = 1000*1007;
void solve(int NT){
int n; cin >> n;
vector<pair<int, int>> v = {{0, 0}};
for(int i = 1; i <= n; ++i) {
int x, y; cin >> x >> y;
v.emplace_back(x, y);
}
int q; cin >> q;
int x; cin >> x;
if(x == 1) {
vector<int> opening(n + 1, 0);
for(int i = 1; i <= n; ++i) {
opening[i] = max(opening[i], v[i].second);
}
int cur = 0, til = 1, ans = 0;
while(til < n) {
int ntil = til;
for(int i = cur + 1; i <= til; ++i) {
ntil = max(ntil, opening[i]);
}
if(ntil == til) break;
cur = til;
til = ntil;
ans++;
}
if(til != n) ans = -1;
cout << ans;
} else {
vector<vector<int>> dp(n + 1, vector<int>(n + 1, INF));
dp[x][x] = 0;
for(int r = 1; r <= n; ++r) {
for(int l = r; l >= 1; --l) {
if(dp[l][r] != INF) {
for(int m = l; m <= r; ++m) {
int nl = min(l, v[m].first);
int nr = max(r, v[m].second);
if(nl != l || r != nr) {
dp[nl][nr] = min(dp[nl][nr], dp[l][r] + 1);
}
}
}
}
}
if(dp[1][n] == INF) dp[1][n] = -1;
cout << dp[1][n];
}
}
// #define TESTCASES
int main() {
cin.tie(0)->sync_with_stdio(0);
int t = 1;
#ifdef TESTCASES
cin >> t;
#endif
for(int i = 1; i <= t; ++i){
solve(i);
cout << "\n";
}
}
