1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
// PA2025, @mjm, r2c-szk

#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
using lol = long long;
inline int nextInt() { int n; scanf("%d", &n); return n; }
inline lol nextLol() { lol n; scanf("%lld", &n); return n; }

lol solve() {
	lol n = nextLol();
	int m = nextInt();
	lol s = nextLol();

	vector<lol> be;
	vector<lol> en;
	for (int i = 0; i < m; ++i) {
		be.push_back(nextLol());
		en.push_back(nextLol());
	}
	sort(be.begin(), be.end());
	sort(en.begin(), en.end());

	auto itBe1 = upper_bound(be.begin(), be.end(), s);
	--itBe1;
	auto itEn1 = lower_bound(en.begin(), en.end(), s);
	auto itBe2 = itBe1;
	auto itEn2 = itEn1;

	lol res1;
	while (true) {
		res1 = (*itBe1) - 1;
		if (itBe1 == be.begin()) break;
		--itBe1;
		--itEn1;
		if ((*itEn1) < res1) break;
	}
	lol res2;
	while (true) {
		res2 = (*itEn2) + 1;
		++itBe2;
		++itEn2;
		if (itEn2 == en.end()) break;
		if (res2 < (*itBe2)) break;
	}

	if (res1 < 1) return res2;
	if (res2 > n) return res1;
	if (res2 - s < s - res1) return res2;
	return res1;
}

int main() {
	lol res = solve();
	printf("%lld\n", res);
	return 0;
}