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#include <cstdio>
#include <unordered_map>
#define ulli unsigned long long int
#define FOR(i,a,b) for(int i=(int)(a); i<(int)(b); ++i)
using namespace std;

int m;
ulli n, s, L0, R0;

int main() {
    scanf("%llu %d %llu", &n, &m, &s);
    unordered_map<ulli, ulli> next;
    FOR(i,0,m) {
        ulli L, R;
        scanf("%llu %llu", &L, &R);

        if (s > R) next[R] = L-1;
        else if (s < L) next[L] = R+1;
        else { L0 = L; R0 = R; }
    }

    ulli resL = L0-1, resR = R0+1;
    while (next.find(resL) != next.end()) resL = next[resL];
    while (next.find(resR) != next.end()) resR = next[resR];

    ulli result;
    if (resL == 0) result = resR;
    else if (resR == n+1) result = resL;
    else if (s - resL <= resR - s) result = resL;
    else result = resR;
    printf("%llu\n", result);
}