#include <cstdio>

using namespace std;

#define FIN "stergeri.in"
#define FOUT "stergeri.out"
#define MAX_M 100005

typedef struct
{
        int x, y;
} point;

point A[MAX_M];
int n, m, k;
int i;

    int main ()
    {
        freopen (FIN, "r", stdin);
        freopen (FOUT, "w", stdout);
        
        scanf ("%d %d %d", &n, &m, &k);
        
        for (i = 1; i <= m; ++i)
            scanf ("%d %d", &A[i].x, &A[i].y);
        
        int T = k;
        for (i = m; i; --i)
            if (A[i].x <= T)
               T = T + (A[i].y - A[i].x + 1);
        
        printf ("%d\n", T);
        
        return 0;
    }