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#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <set>

int c;

void SKIP_WHITESPACE() {
    while (1) {
        c = fgetc(stdin);
        if (c != ' ' && c != '\n' && c != '\r')
            break;
    }
}

int READ_INT() {
    SKIP_WHITESPACE();
    int ret = c - '0';
    while (1) {
        c = fgetc(stdin);
        if (c < '0' || c > '9')
            break;
        ret = ret * 10 + c - '0';
    }
    return ret;
}

int64_t READ_INT64() {
    SKIP_WHITESPACE();
    int64_t ret = c - '0';
    while (1) {
        c = fgetc(stdin);
        if (c < '0' || c > '9')
            break;
        ret = ret * 10 + c - '0';
    }
    return ret;
}

int64_t n, s, a, b, maks, woh;
int m;

struct elem {
    int64_t a;
    int64_t b;

    bool operator<(const elem& par) const {
        return a < par.a;
    }
};

std::set<elem> prim, sec;

int main(int argc, char* argv[]) {
    std::ios_base::sync_with_stdio (false);

    n = READ_INT64();
    m = READ_INT();
    s = READ_INT64();
    for (int i = 0; i < m; ++i) {
        a = READ_INT64();
        b = READ_INT64();
        prim.insert({a, b});
    }

    a = -1;
    b = -1;
    for (const auto& e : prim) {
        if (e.a > b + 1) {
            if (a <= s && s <= b) {
                maks = n + 1;
                if (a - 1 > 0) {
                    maks = s - a + 1;
                    woh = a - 1;
                }
                if (b + 1 <= n) {
                    if (b + 1 - s < maks) {
                        maks = b + 1 - s;
                        woh = b + 1;
                    }
                } 
            }
            a = e.a;
            b = e.b;
            continue;
        }
        b = e.b;
    }
    if (a <= s && s <= b) {
        maks = n + 1;
        if (a - 1 > 0) {
            maks = s - a + 1;
            woh = a - 1;
        }
        if (b + 1 <= n) {
            if (b + 1 - s < maks) {
                maks = b + 1 - s;
                woh = b + 1;
            }
        }
    }

    std::cout << woh << "\n";
    return EXIT_SUCCESS;
}