#include<stdio.h>
int n,t,p,m[2][100010],i;

int main(){

FILE *f=fopen("stergeri.in","r");
fscanf(f,"%d %d %d",&n,&t,&p);

 for(i=1;i<=t;i++){
 fscanf(f,"%d %d",&m[0][i],&m[1][i]);
 }


 for(i=t;i>=1;i--){
   if(m[0][i]<p){
   p+=(m[1][i]-m[0][i]+1);
   }

 }


fclose(f);



FILE *g=fopen("stergeri.out","w");
fprintf(g,"%d",p);
fclose(g);

return 0;
}