#include <fstream>
#define MMAX 100001
using namespace std;

struct interv
{   int x, y;
} v[MMAX];

int n, m, i, k, U[MMAX], ok;

ifstream f("stergeri.in");
ofstream g("stergeri.out");

int main()
{   f>>n>>m>>k;
    for (i=1; i<=m; ++i)
        f>>v[i].x>>v[i].y;
    while (1)
    {   ok=0;
        for (i=1; i<=m; ++i)
            if (!U[i] && k>=v[i].x)
            {   ok=1;
                k+=v[i].y-v[i].x+1;
                U[i]=1;
            }
        if (!ok)
            break;
    }
    g<<k<<'\n';
    return 0;
}