Pagini recente » Cod sursa (job #2698387) | Cod sursa (job #2946383) | Cod sursa (job #2551417) | Cod sursa (job #1313695) | Cod sursa (job #3249753)
#include <iostream>
#include <fstream>
#include <vector>
#define int long long
using namespace std;
ifstream fin("frac.in");
ofstream fout("frac.out");
vector <int> v,prim;
bool ciur[1000005];
void precalc()
{
ciur[1]=1;
ciur[0]=1;
for (int i=2; i*i<=1000000; i++)
if (!ciur[i]) for (int j=i*i; j<=1000000; j+=i)
ciur[j]=1;
for (int i=2; i<=1000000; i++)
if (!ciur[i]) prim.push_back(i);
}
int sub(int n,int a)
{
int l=1<<n,s=0;
for (int i=1; i<=l; i++)
{
int p=1,nr=0;
for (int j=0; j<n; j++)
{
if (i & (1<<j)) p=p*v[j],nr++;
}
//cout<<p<<' ';
if (nr%2==0) s+=a/p;
else s-=a/p;
}
//cout<<'\n';
return s;
}
int nrprime(int n,int a)
{
int c=a,k=0,d=prim[k];
while (d*d<=c)
{
int e=0;
while (c%d==0)
{
c/=d;
e++;
}
if (e) v.push_back(d);
k++;
d=prim[k];
}
if (c!=1) v.push_back(c);
int p=sub(v.size(),n);
v.clear();
return p;
}
int n,x;
int32_t main()
{
fin>>n>>x;
precalc();
cout<<nrprime(13,12);
int st=1,dr=12000000000,ans=0;
while (st<=dr){
int mij=(st+dr)/2;
int k=nrprime(mij,n);
//cout<<k;
if (k>=x) ans=mij,dr=mij-1;
else st=mij+1;
}
fout<<ans;
return 0;
}