#include <fstream>
#define DIM 100001

using namespace std;

ifstream fin("stergeri.in");
ofstream fout("stergeri.out");
int a[DIM],b[DIM];
int n,m,i,x,y,nr,k;
int main(){
    fin>>n>>m>>k;
    for(i=1;i<=m;i++){
        fin>>a[i]>>b[i];
    }
    for(i=m;i>=1;i--)
        if(a[i]<=k)
            k+=b[i]-a[i]+1;
    fout<<k;
    return 0;
}