//stergeri-arena
#include <bits/stdc++.h>
using namespace std;

ifstream fin ("stergeri.in");
ofstream fout ("stergeri.out");

int main(){
    long long N, M, i, K, x, y, dif[100001], v[100001];
    fin>>N>>M>>K;

    for(i=1; i<=M; i++){
        fin>>v[i]>>y;
        dif[i]=y-v[i]+1;
    }
    
    sort(v+1,v+M+1);

    for(i=1; i<=M; i++){
        if(v[i]<=K){
            K=K+dif[i];
        }
    }
    
    fout<<K;
    
    
}