#include<stdio.h>
#include<utility>
#include<vector>
using namespace std;
std::vector < pair < int, int > >::iterator it;
int main()
{
    int N,M,K,a,b;
    vector < pair < int, int > > interval;
    freopen("stergeri.in","r",stdin);
    freopen("stergeri.out","w",stdout);
    scanf("%d %d %d",&N,&M,&K);
    for(int i=1;i<=M;++i)
        scanf("%d%d",&a,&b),interval.push_back(make_pair(a,b));
    int SOL=K;
    for(it=interval.end();it>=interval.begin();it--)
        if(it->first<=SOL)
            SOL+=it->second-it->first+1;
    printf("%d",SOL);
    fclose(stdin);fclose(stdout);
    return 0;
}