#include <bits/stdc++.h>

using namespace std;

int n, m, k, sol;
stack< pair<int, int> > s;

int main()
{
    ifstream fin ("stergeri.in");
    ofstream fout ("stergeri.out");
    fin >> n >> m >> k; sol = k;
    while(m--){
        int x, y;
        fin >> x >> y;
        s.push({x, y-x+1});
    }
    while(!s.empty()){
        if(s.top().first <= sol)
            sol += s.top().second;
        s.pop();
    }
    fout << sol << "\n";
    fin.close();
    fout.close();
    return 0;
}