#include <iostream>
#include <fstream>

using namespace std;

const int  MMAX=100001;


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

long long n;
int m, k, a[MMAX], b[MMAX];

void citire()
{
    fin>>n>>m>>k;
    for(int i=1;i<=m;i++)
        fin>>a[i]>>b[i];
}
void rezolvare()
{
    for(int i=m;i>=1;i--)
    {
        if(a[i]<=k) k+=b[i]-a[i]+1;
    }
    cout<<k;
}
int main()
{
    citire();
    rezolvare();
    return 0;
}