#include <fstream>
#define NM 100005

using namespace std;

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

int n,m,k,i,a[NM],b[NM];

int main()
{
    fin >> n >> m >> k;
    for (i=1; i<=m; i++)
      fin >> a[i] >> b[i];
    for (i=m; i>=1; i--)
    {
        if (k>=a[i])
        {
            b[i]-=a[i];
            b[i]++;
            k+=b[i];
        }
    }
    fout << k << '\n';
    fin.close();
    fout.close();
    return 0;
}