#include <cstdio>
#define MAXN 100000
int st[MAXN+1],dr[MAXN+1];
int main(){
    FILE*fi,*fout;
    int i,n,m,k,ans;
    fi=fopen("stergeri.in" ,"r");
    fout=fopen("stergeri.out" ,"w");
    fscanf(fi,"%d %d %d " ,&n,&m,&k);
    for(i=1;i<=m;i++)
      fscanf(fi,"%d %d " ,&st[i],&dr[i]);
    ans=k;
    for(i=m;i>0;i--)
      if(st[i]<=ans)
       ans+=dr[i]-st[i]+1;
    fprintf(fout,"%d" ,ans);
    fclose(fi);
    fclose(fout);
    return 0;
}