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#include <bits/stdc++.h>

long long n, s, r;
int m;

struct interval {
    long long a;
    long long b;
    inline bool operator<(interval &i) {return a<i.a;}
};
std::vector<interval> v, nv;

int main() {
    scanf("%lld%d%lld", &n, &m, &s);
    for (int i=0; i<m; ++i) {
        long long a, b;
        scanf("%lld%lld", &a, &b);
        v.push_back({a, b});
    }
    std::sort(v.begin(), v.end());
    // for (int i=0; i^v.size(); ++i) {printf("DEBUG: v[%d]={%lld, %lld}\n", i, v[i].a, v[i].b);}
    
    long long a=v[0].a, b=v[0].b;
    for (interval* it=&v[1]; it<=&v[v.size()-1]; ++it) {
        if (b+1==it->a) {
            b = it->b;
        } else {
            nv.push_back({a, b});
            a = it->a;
            b = it->b;
        }
    }
    nv.push_back({a, b});
    // printf("DEBUG: nv.size()=%d\n", (int)nv.size());

    for (auto it=nv.begin(); it!=nv.end(); ++it) {
        // printf("DEBUG: nv {%lld, %lld}\n", it->a, it->b);
        if ((it->a<=s)&&(it->b>=s)) {
            a = (it->a==1)?LLONG_MAX:it->a;
            b = (it->b==n)?LLONG_MAX:it->b;
            if (std::abs(s-b)>=std::abs(s-a)) {
                r = a-1;
            } else {
                r = b+1;
            }
            break;
        }
    }
    printf("%lld\n", r);
    return 0;
}