#include <fstream>

using namespace std;
    ifstream f("stergeri.in");
    ofstream g("stergeri.out");

int n, m, k, x[100002], y[100002];

int main()
{   f>>n>>m>>k;
    for (int i=1; i<=m; ++i)
        f>>x[i]>>y[i];
    for (int i=m; i>0; --i)
        if (x[i]<=k) k+=(y[i]-x[i]+1);
    g<<k;
    return 0;
}