#include<fstream>
using namespace std;
ifstream f("stergeri.in");
ofstream g("stergeri.out");
int n,m,k,i,a[100001],b[100001];
int main()
{   f>>n>>m>>k;
    for(i=1;i<=m;++i) f>>a[i]>>b[i];
    for(i=m;i>=1;--i)
        if(a[i]<=k) k+=b[i]-a[i]+1;
    g<<k<<'\n';
	g.close();
	return 0;
}