#include <fstream>
#define MMAX 100001
using namespace std;

struct interv
{   int x, y;
} v[MMAX];

int n, m, i, k;

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

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