#include <stdio.h>

FILE *f,*s;

long int n,m,k,i,rez,m1[100005],m2[100005];

int main()
{
	f=fopen("stergeri.in","r");
	s=fopen("stergeri.out","w");
	
	fscanf(f,"%ld %ld %ld\n",&n,&m,&k);
	
	rez=k;
	for(i=1;i<=m;i++)
		fscanf(f,"%ld %ld\n",&m1[i],&m2[i]);
	
	rez=k;
	for(i=m;i>=1;i--)
	{
		if(m1[i]<rez)
			rez+=m2[i]-m1[i]+1;
	}	

	fprintf(s,"%ld",rez);
	
	fclose(s);
	
	return 0;
}