#include<fstream>
#define maxm 100005

using namespace std;

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

int n,m,i,k;

struct nod
{
    int x,y;
} a[maxm];

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

    for(i=1;i<=m;++i)
        f>>a[i].x>>a[i].y;

    for(i=m;i;--i)
        if(a[i].x<=k)
            k+=a[i].y-a[i].x+1;

    g<<k<<"\n";

    f.close();
    g.close();

    return 0;
}