#include <fstream>
using namespace std;
ifstream f("stergeri.in");
ofstream g("stergeri.out");

int n, m, k, inf[100005], sup[100005], sum;

int main()
{
    f >> n >> m >> k;
    int sum = k;

    for (int i = 0; i < m; i ++)
        f >> inf[i] >> sup[i];

    for (int i = m - 1; i >= 0; i --)
    {
        if (inf[i] <= sum)
            sum += (sup[i] - inf[i] + 1);
    }
    g << sum;
    f.close();
    g.close();
    return 0;
}