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#include <bits/stdc++.h>

using namespace std;

struct Range
{
    long long int start, end;
};

bool sort_ranges_by_start(const Range& a, const Range& b)
{
    return a.start < b.start;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    
    long long int buildings_cnt, school;
    int ranges_cnt;
    int i;
    
    cin >> buildings_cnt >> ranges_cnt >> school;
    
    vector<Range> ranges(ranges_cnt);
    for (auto& range : ranges)
    {
        cin >> range.start >> range.end;
    }
    
    // Sentinels
    ranges.push_back({ buildings_cnt + 1, buildings_cnt + 1 });
    ranges.push_back({ 0, 0 });
    ranges_cnt += 2;
    sort(ranges.begin(), ranges.end(), sort_ranges_by_start);
    
    int school_range_idx = -1;
    for (i = 0; i < ranges_cnt; ++i)
    {
        if (ranges[i].start <= school && ranges[i].end >= school)
        {
            school_range_idx = i;
            break;
        }
    }
    assert(school_range_idx != -1);
    
    long long int min_dist = numeric_limits<long long int>::max();
    long long int building;
    long long int res = -1;
    for (i = school_range_idx + 1; i < ranges_cnt; ++i)
    {
        building = ranges[i - 1].end + 1;
        if (ranges[i].start > building)
        {
            res = building;
            min_dist = building - school;
            break;
        }
    }
    
    for (i = school_range_idx - 1; i >= 0; --i)
    {
        building = ranges[i + 1].start - 1;
        if (ranges[i].end < building)
        {
            long long int dist = school - building;
            
            if (dist < min_dist)
            {
                res = building;
            }
            else if (dist == min_dist)
            {
                res = min(res, building);
            }
            
            break;
        }
    }
    
    assert(res != -1);
    cout << res << "\n";

    return 0;
}