using namespace std;
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <set>
#define maxn 600011

set<int>H[maxn];

inline void insert(int v)
{
	H[v%maxn].insert(v);
}

inline int find(int v)
{
	return H[v%maxn].find(v)!=H[v%maxn].end();
}

int main()
{
	srand(time(0));
	double s=clock();
	for(int i=1;i<=1000000;++i) insert(rand());
	for(int i=1;i<=1000000;++i) find(rand());
	
	printf("%lf\n", (clock()-s)/(double)CLOCKS_PER_SEC);
	
	
	return 0;
}