#include <fstream>

using namespace std;

ifstream fin ("stergeri.in");
ofstream fout ("stergeri.out");

struct inv
{
    int dr, st;
};
inv a[100001];
int main()
{
    int n, k, m;
    fin >>m >> n>> k;
    for (int i=1; i<=n;i++)fin >> a[i].st >> a[i].dr;
    for (int i =n; i>=1; i--)
    {
        if (a[i].st <= k)k+=a[i].dr - a[i].st+1;
    }
    return 0;
}