#include <stdio.h>
int n,m,k;
struct mata
{
    int st,dr;
} a[100001];
int main ()
{
    freopen ("stergeri.in","r",stdin);
    freopen ("stergeri.out","w",stdout);
    int i;
    scanf ("%d%d%d",&n,&m,&k);
    for (i=1; i<=m; ++i)
        scanf ("%d%d",&a[i].st,&a[i].dr);
    for (i=n; i; --i)
        if (a[i].st<=k)
            k+=a[i].dr-a[i].st+1;
    printf ("%d",k);
    return 0;
}