poj 2773

#include<iostream>
#include<fstream>
#include<cmath>

using namespace std;

int a[1001];
int b[1000001];
int n,m;

void read(){
//	ifstream cin("in.txt");
int i,j,k,ans,s;
for(i=4;i<=1000;i+=2)
a[i]=1;
for(i=3;i<=1000;i+=2)
if(a[i]==0)
for(j=2*i;j<=1000;j+=i)
a[j]=1;
while(cin>>n>>m){
s=n;ans=1;
memset(b,0,sizeof(b));

for(i=2;i<=n&&i*i<=s;i++)
if(a[i]==0&&n%i==0)
{
j=0;
while(n%i==0)
{
n/=i;
j++;
}
ans*=pow(1.*i,j-1)*(i-1);
for(j=i;j<=s;j+=i)
b[j]=1;
}
if(n>1)
{
ans*=n-1;
for(j=n;j<=s;j+=n)
b[j]=1;
}
k=(m-1)%ans;
k++;
j=0;
for(i=1;i<=s;i++)
if(b[i]==0)
{
j++;
if(j==k)
break;
}
cout<<(m-1)/ans*s+i<<endl;
}

}

int main(){
read();
return 0;
}