#include<iostream.h>
#include<fstream.h>
#define cin fin
#define cout fout

long n,m,k,x,y,i,s,f;

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

    cin>>n>>m>>k;

    s=n;

    for(i=1;i<=m;++i)
        {
        cin>>x>>y;
        if(x<=k)
            k+=y-x+1;
        if(x>k)
            {
            if(x<s)
                s=x;
            f+=y-x+1;
            }
        if(k>=s)
            k+=f;
        }
cout<<k;

fin.close();
fout.close();
return 0;
}