#include <iostream>
#include <cstdio>
using namespace std;
#include <vector>
int x,y,n,m,k,i;
int main()
{
  //  std::ios::sync_with_stdio(false);
    freopen("stergeri.in","r",stdin);
    freopen("stergeri.out","w",stdout);
    vector<int> a,b;
    cin>>n>>m>>k;
    for (i=0;i<m;i++)
    {
        cin>>x>>y;
        a.push_back(x);
        b.push_back(y);
    }
    for (i=m-1;i>=0;i--)
    {
        if (a[i]<k) k+=b[i]-a[i]+1;
    }
    cout<<k;

}