26 lines
472 B
C++
26 lines
472 B
C++
#include<iostream>
|
|
#include<cstring>
|
|
using namespace std;
|
|
const int MAX=3000004;
|
|
long long e[MAX];
|
|
void euler()
|
|
{
|
|
e[1]=0;
|
|
for(int i=2;i<MAX;++i)
|
|
e[i]=i;
|
|
for(int i=2;i<MAX;++i)
|
|
if(e[i]==i)
|
|
for(int j=i;j<MAX;j+=i)
|
|
e[j]=e[j]/i*(i-1);
|
|
for(int i=2;i<MAX;++i)
|
|
e[i]+=e[i-1];
|
|
}
|
|
int main()
|
|
{
|
|
euler();
|
|
int a,b;
|
|
while(cin>>a>>b)
|
|
cout<<e[b]-e[a-1]<<endl;
|
|
return 0;
|
|
}
|