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#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

long long int n, s;
int m;
vector<pair<long long, long long>> intervals;


int findInterval(long long val)//bs
{
	for (int i = 0; i < m; i++)
	{
		if (val >= intervals[i].first && val <= intervals[i].second)
		{
			return i;
		}
	}

	return -1;
}

int main()
{
	long long res_val = 100000000000000LL;
	long long res_idx = -1;

	cin >> n >> m >> s;

	intervals = vector<pair<long long, long long>>(m);

	for (int i = 0; i < m; i++)
	{
		long long int a, b;
		cin >> a >> b;

		intervals[i] = make_pair(a, b);
	}

	sort(intervals.begin(), intervals.end());

	int baseIndex = findInterval(s);

	long long int val_left, val_right;
	int idx_left, idx_right;

	if (baseIndex == -1)
	{
		//lewo
		if (s - 1 < 1)
		{
			goto nima;
		}

		baseIndex = findInterval(s - 1);

		if (baseIndex == -1)
		{
			res_idx = s - 1;
			res_val = 1;

			cout << res_idx;
			return 0;
			//koniec
		}
		else
		{
			//nic
		}

		//prawo
		if (s + 1 > n)
		{

		}
		else
		{
			baseIndex = findInterval(s + 1);

			if (baseIndex == -1)
			{
				res_idx = s + 1;
				res_val = 1;

				cout << res_idx;
				return 0;
			}
		}

	}

	idx_left = baseIndex;

	do {
		val_left = intervals[idx_left].first - 1;
		idx_left = idx_left - 1;

		if (val_left < 1)
		{
			goto nima;
		}

		if (idx_left < 0)
		{
			break;
		}


	} while (val_left == intervals[idx_left].second);

	res_idx = val_left;
	res_val = s - val_left;

nima:
	//prawo

	idx_right = baseIndex;

	do {
		val_right = intervals[idx_right].second + 1;
		idx_right = idx_right + 1;

		if (val_right > n)
		{
			goto nima2;
		}

		if (idx_right >= m)
		{
			break;
		}


	} while (val_right == intervals[idx_right].first);

	if (val_right - s < res_val)
	{
		res_idx = val_right;
	}

	nima2:

	cout << res_idx;
}