#include <bits/stdc++.h>
using namespace std;
int main() {
int l,r,x;
cin >> l >> r >> x;
int poss = 0;
for(int i = l; i <= r; i++){
for(int j = i+1; j <= r; j++){
if((i ^ j) == x) poss++;
}
}
cout << poss;
return 0;
}
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