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#include <cstdio>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <queue>
#include <list>
#include <vector>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <set>
#include <bitset>
#include <stack>
#include <string>
#include <cstring>
#include <cassert>
#include <limits.h>

using namespace std;

typedef unsigned long long LL;
typedef long double LD;

typedef vector<int> VI;
#define REP(i,n) for(int i=0;i<(n);i++)
#define FOR(i,a,b) for(VAR(i,a);i<=(b);++i)
#define FORD(i,a,b) for(VAR(i,a);i>=(b);--i)
#define FORE(a,b) for(VAR(a,(b).begin());a!=(b).end();++a)
#define VAR(a,b) __typeof(b) a=(b)
#define SIZE(a) ((int)((a).size()))
#define ALL(x) (x).begin(),(x).end()
#define CLR(x,a) memset(x,a,sizeof(x))
#define ZERO(x) memset(x,0,sizeof(x))
#define S(t,i) scanf("%" ## t, &i)
#define SI(i) scanf("%d", &i)

const int MAXN=8000+11;
char schedule[MAXN];
set<LL> ls, rs;

LL n, m, s;
LL b=10000000000000LL;
LL min_dist=10000000000000LL;
int main() {
    ios_base::sync_with_stdio(0);
    cin >> n;
    cin >> m;
    cin >> s;
    set<LL>::iterator lit;
    set<LL>::iterator rit;

    REP(i, m) {
        LL li, ri;
        cin >> li >> ri;
        set<LL>::iterator liti = ls.insert(li).first;
        set<LL>::iterator riti = rs.insert(ri).first;
        if (s>=li && s<=ri) {
            lit = liti;
            rit = riti;
        }
    }

    set<LL>::iterator it = lit;
    while (it!=ls.end()) {
        LL firstFree = (*it)-1;
        if (rs.find(firstFree) == rs.end()) {
            if (firstFree >= 1) {
                b = firstFree;
                min_dist = s-b;
            }
            break;
        } else {
            --it;
        }
    }

    it = rit;
    while (it != rs.end()) {
        LL firstFree = (*it)+1;
        if (ls.find(firstFree) == ls.end()) {
            if (firstFree <= n && min_dist > firstFree - s) {
                b = firstFree;
            }
            break;
        } else {
            ++it;
        }
    }

    cout << b << "\n";

    return 0;
}