#include <fstream>
#include <stack>

using namespace std;

struct TData
{
    int p,k;
};

stack<TData> insers;

int main()
{
    ifstream fIn ("stergeri.in");
    ofstream fOut ("stergeri.out");

    int n,m,k;
    fIn >> n >> m >> k;

    for(int i = 0; i < m; ++i)
    {
         int a,b;
         fIn >> a >> b;
         insers.push((TData){a,b-a+1});
    }

    while(!insers.empty())
    {
        TData t = insers.top();
        insers.pop();
        if(t.p<=k)k+=t.k;
    }
    fOut << k;
}