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#include <iostream>
#include <map>

using range_map_t = std::map<uint64_t, uint64_t>;

uint64_t first_empty_lower(range_map_t &m, range_map_t::iterator &it) {
	auto begin = it->first;
	while (it != m.begin()) {
		--it;
		if (begin - it->second > 1)
		{
			return begin - 1;
		}
		else {
			begin = it->first;
		}
	}
	if (begin > 1) {
		return begin - 1;
	}
	return 0;
}

uint64_t first_empty_higher(uint64_t n, range_map_t &m, range_map_t::iterator &it) {
	auto end = it->second;
	while (it != m.end()) {
		++it;
		if (it == m.end()) {
			break;
		}

		if (it->first - end > 1)
		{
			return end + 1;
		}
		else {
			end = it->second;
		}
	}
	if (end < n) {
		return end + 1;
	}
	return 0;
}

void prog_main(std::istream& in, std::ostream& out)
{
	uint64_t n, m, s;
	in >> n;
	in >> m;
	in >> s;
	range_map_t ranges;
	for (uint64_t i = 0; i < m; ++i) {
		uint64_t l, r;
		in >> l;
		in >> r;
		ranges.emplace(std::make_pair(l, r));
	}
	auto result = ranges.emplace(std::make_pair(s,s));
	range_map_t::iterator it;
	uint64_t sch_range = s;
	if (result.second)
	{
		it = result.first;
		--it;
		sch_range = it->first;
		++it;
		ranges.erase(it);
		it = ranges.find(sch_range);
	} else {
		it = result.first;
		sch_range = it->first;
	}

	uint64_t lower = first_empty_lower(ranges, it);
	it = ranges.find(sch_range);
	uint64_t higher = first_empty_higher(n, ranges, it);
	if (lower == 0) {
		out << higher << std::endl;
		return; 
	}
	if (higher == 0) {
		out << lower << std::endl;
		return;
	}
	
	if (s - lower <= higher -s) {
		out << lower << std::endl;
	} else {
		out << higher << std::endl;
	}
}

#ifndef TEST
int main(int argc, char* argv[])
{
	prog_main(std::cin, std::cout);
	return 0;
}
#endif