#include <fstream>
using namespace std;
ifstream f("stergeri.in");
ofstream g("stergeri.out");

int N, M, K;
long long sol;
struct interval{ int x, y; }a[100005];

int main()
{
    f>>N>>M>>K;
    sol=K;
    for (int i=1; i<=M; ++i)
        f>>a[i].x>>a[i].y;

    for (int i=M; i>0; --i)
        if (a[i].x<sol) sol+=(a[i].y-a[i].x+1);

    g<<sol<<'\n';
    return 0;
}