#include <iostream>
#include<fstream>
#include<stack>
#define mkp make_pair
using namespace std;
ifstream si("stergeri.in");
ofstream so("stergeri.out");
stack< pair<int,int> > s;
int main()
{
    int n,m,k,i,a,b;
    si>>n>>m>>k;
    for(i=0;i<m;++i)
    {
        si>>a>>b;
        s.push(mkp(a,b));
    }
    while(!s.empty())
    {
        a=s.top().first;
        b=s.top().second;
        s.pop();
        if(a<=k)
            k+=b-a+1;
    }
    so<<k<<'\n';
    return 0;
}