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#include<cstdio>
#include<vector>
#include<utility>
#include<algorithm>

using namespace std;

int main() {
    long long buildingsNum;
    int intervalsNum;
    long long school;

    scanf("%lld %d %lld\n", &buildingsNum, &intervalsNum, &school);

    vector<pair<long long, long long> > intervals;
    for (int i = 0; i < intervalsNum; i++) {
        long long left;
        long long right;

        scanf("%lld %lld\n", &left, &right);

        pair<long long, long long> interval(left, right);
        intervals.push_back(interval);
    }

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

    long long lastFromLeft = buildingsNum + 1;
    long long firstFromRight = -1;
    
    int i = 0;
    while (intervals[i].first > school || intervals[i].second < school) { 
        if (i == 0) {
            if (intervals[i].first > 1) {
                lastFromLeft = intervals[i].first - 1;
            }
        } else {
            if (intervals[i].first > intervals[i - 1].second + 1) {
                lastFromLeft = intervals[i].first - 1;
            }
        }

        i++;
    }

    if (i == 0) {
        if (intervals[i].first > 1) {
            lastFromLeft = intervals[i].first - 1;
        }
    } else {
        if (intervals[i].first > intervals[i - 1].second + 1) {
            lastFromLeft = intervals[i].first - 1;
        }
    }

    while (i + 1 < intervalsNum && intervals[i + 1].first == intervals[i].second + 1) {
        i++;
    }

    if (i + 1 < intervalsNum) {
        firstFromRight = intervals[i].second + 1;
    } else if (intervals[i].second < buildingsNum) {
        firstFromRight = intervals[i].second + 1;
    }

    long long leftDistance = buildingsNum;
    long long rightDistance = buildingsNum;

    if (lastFromLeft < school) {
        leftDistance = school - lastFromLeft;
    }
    if (firstFromRight > school) {
        rightDistance = firstFromRight - school;
    }

    if (rightDistance < leftDistance) {
        printf("%lld\n", firstFromRight);
    } else {
        printf("%lld\n", lastFromLeft);
    }

    return 0;
}