#include <fstream>
 
using namespace std;
 
ifstream f("stergeri.in");
ofstream g("stergeri.out");
 
const int MAX_M = 100005;
 
int n, m, k, a[MAX_M], b[MAX_M];
 
int main()
{
    f >> n >> m >> k;
    for (int i = 1; i <= m; i++)
        f >> a[i] >> b[i];
     
    for (int i = m; i >= 1; i--)
        if (a[i] <= k)
            k += b[i] - a[i] + 1;
         
    g << k << '\n';
     
    return 0;
}