#include <stdio.h>

int e[100004];
int f[100004];
int main()
{
	int n,m,k,a,b,i;
	FILE *f1,*f2;
	f1=fopen("stergeri.in","r");
	f2=fopen("stergeri.out","w");
	fscanf(f1,"%d %d %d",&n,&m,&k);
	for(i=m;i>=1;i--)

		fscanf(f1,"%d %d",&e[i],&f[i]);
	for(i=1;i<=m;i++)
		if(e[i]<=k)
			k=k+f[i]-e[i]+1;
	fprintf(f2,"%d",k);
	fclose(f1);
	fclose(f2);

	return 0;
}