#include <fstream>
#define x first
#define y second
#define dim (int)(1e5+1)
using namespace std;
ifstream cin("stergeri.in");
ofstream cout("stergeri.out");
int n,m,k;
pair<int,int>v[dim];
signed main()
{
    cin>>n>>m>>k;
    for(int i=1;i<=m;i++)
        cin>>v[i].x>>v[i].y;
    for(int i=m;i>0;i--)/// in loc sa eliminam adaugam
        if(v[i].x<=k)
            k+=(v[i].y-v[i].x+1);
    cout<<k;
    return 0;
}