#include <iostream>
#include <fstream>
 
using namespace std;
 #define Nmax 100005
 int N, M, K;
 
int x[Nmax], y[Nmax];
 
int main()
{
    ifstream f("stergeri.in");
    ofstream g("stergeri.out");
 
    f >> N >> M >> K;
 
    for ( int i = 1; i <= M; ++i )
            f >> x[i] >> y[i];
 
    for ( int i = M; i >= 1; i-- )
    {
        if ( x[i] > K )
                continue;
 
        K += y[i] - x[i] + 1;
    }
 
    g << K << "\n";
 
    f.close();
    g.close();
 
    return 0;
}