#include <fstream>
#include <algorithm>
using namespace std;

int n, m, k, i, v[100005], w[100005];

int main ()
{
    ifstream fin ("diagonala.in");
    ofstream fout("diagonala.out");

    fin>>n>>m>>k;
    for (i=1; i<=n; i++)
    {
        fin>>v[i]>>w[i];
    }
    for(i=m;i>=1;i--)
        if(k>v[i])
            k+=w[i]-v[i]+1;

    fout<<k;
    return 0;
}