#include <bits/stdc++.h>

using namespace std;

ifstream fin ("stergeri.in");
ofstream fout ("stergeri.out");

pair <int,int> v[100005];

int main()
{
    int n,m,k;
    fin >> n >> m >> k;
    for (int i=1;i<=m;++i){
        int x,y;
        fin >> x >> y;
        v[i] = {x,y};
    }
    int ans = k;
    for (int i=m;i>=1;i--){
        if (v[i].first<=ans){
            ans += v[i].second-v[i].first+1;
        }
    }
    fout << ans;
    return 0;
}