#include <fstream>

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

int main()
{   unsigned long n, a, m, k, x, y;
    f>>n>>m>>k;
    a=k;
    for (unsigned long i=1; i<=m; ++i)
    {   f>>x>>y;
        if (x<a) a=a+x+y+1; }
    g<<a;
    return 0;
}