#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>using namespace std;long long x,y,z;long long Calculate(long long a,long long b,long long c,long long n){ if(n==0) return 0; return (b/c)*n+(a/c)*n*(n-1)/2+Calculate(c,(a*n+b)%c,a%c,(a%c*n+b%c)/c);}int main(){ int i; while(cin>>x>>y>>z) { long long ans=0; for(i=0;i<32;i++) ans|=(Calculate(z,x,1ll<<i,(y-x)/z+1)&1ll)<<i; cout<<ans<<endl; } return 0;}
