#include <bits/stdc++.h>
#include "testlib.h"
using namespace std;

int main(int argc, char* argv[]) {
    registerValidation(argc, argv);
    int n = inf.readInt(1, 1000000000);
    inf.readEoln();
    inf.readEof();
    cout << ((n % 2 == 0) ? (n / 2 + 1) : 1) << endl;
}