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

using namespace std;

int main()
{
    int n,m,s;
    int RESULT;
    cin >> n;
    cin >> m;
    cin >> s;
    vector<int> l(m);
    vector<int> r(m);
    for(int i=0;i<m;i++)
    {
        cin >> l[i];
        cin >> r[i];
    }
    sort(l.begin(),l.end());
    sort(r.begin(),r.end());
    int L = 0;
    int R= 0;
    int LEFT;
    int RIGHT;
    while(r[R] < s)
    {
        L++;
        R++;
    }
    int L_save = L;
    int R_save = R;
    while((r[R-1] == l[L]-1) && R >=1)
    {
        L--;
        R--;
    }
    if(l[L] != 1)
    {
        LEFT = l[L]-1;
    }
    else
    {
        LEFT = 0;
    }
    L = L_save;
    R = R_save;
    while((l[L+1] == r[R]+1) && L <= m-1)
    {
        L++;
        R++;
    }
    if(r[R] != n)
    {
        RIGHT = r[R]+1;
    }
    else
    {
        RIGHT = 0;
    }
    if(LEFT == 0)
    {
        RESULT = RIGHT;
    }
    else if(RIGHT == 0)
    {
        RESULT = LEFT;
    }
    else
    {
        if( (s-LEFT) <= (RIGHT-s))
        {
            RESULT = LEFT;
        }
        else
        {
            RESULT = RIGHT;
        }
    }
    cout << RESULT;
}