#include<cstdio>
#define maxn 100005
using namespace std;
int m,n,k,i,a[maxn][2];
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",&a[i][0],&a[i][1]);
  for(i=m;i;--i) if(a[i][0]<=k) k+=a[i][1]-a[i][0]+1;
  printf("%d\n",k);
  fclose(stdin);
  fclose(stdout);
  return 0;
}