#include<cstdio>
#include<algorithm>
#include<cstring>
#define Nmax 100005
using namespace std;
int n,m,k,i,j,valk;
struct nod
{
    int x;
    int y;
}v[Nmax];
int main()
{
    freopen("stergeri.in","r",stdin);
    freopen("stergeri.out","w",stdout);
    scanf("%d %d %d",&n,&m,&k);
    for (i=1;i<=m;i++)
    scanf("%d %d",&v[i].x,&v[i].y);
    valk=k;
    for (i=m;i>=1;i--)
    if (v[i].x<=valk)
    valk+=v[i].y-v[i].x+1;
    printf("%d",valk);
    return 0;
}