#include <fstream>
#define in "stergeri.in"
#define out "stergeri.out"
#define Max_Size 100009

std :: ifstream f(in);
std :: ofstream g(out);

int N, M, K;
struct obj
{
    int x;
    int y;
}   C[Max_Size];

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

    for(int i = M; i >= 1; --i)
        if(C[i].x <= K) K += C[i].y - C[i].x + 1;

    g << K << '\n';

    g.close();
    return 0;
}