#include<cstdio>

const int N=100005;

int n,m,k,a[N],b[N];

int main()
{
	freopen("stergeri.in","r",stdin);
	freopen("stergeri.out","w",stdout);
	scanf("%d%d%d",&n,&m,&k);
	for (int i=1;i<=m;++i)
		scanf("%d%d",&a[i],&b[i]);
	for (int i=m;i>0;--i)
		if (a[i]<=k)
			k+=(b[i]-a[i]+1);
	printf("%d\n",k);
	return 0;
}