#include <iostream>
#include <fstream>
using namespace std;
ifstream fi("stergeri.in");
ofstream fo("stergeri.out");
int n,m,k,a[100010],b[100010];
int main(){
    fi>>n>>m>>k;
    for (int i=1;i<=m;++i) fi>>a[i]>>b[i];
    for (int i=m;i>0;--i) if (a[i]<=k) k+=b[i]-a[i]+1;
    fo<<k;
    return 0;
}