#include <bits/stdc++.h>

using namespace std;

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

int n,op,k;
int st[100005],dr[100005];


int main()
{
    int i,ans;
    fin>>n>>op>>k;
    ans=k;
    for(i=1;i<=op;i++)
    {
        fin>>st[i]>>dr[i];
    }
    for(i=op;i>=1;i--)
    {
        if(ans>=st[i])
            ans+=dr[i]-st[i]+1;
    }
    fout<<ans;
    return 0;
}