#include<bits/stdc++.h>
#include<ext/numeric>
#define fastIO ios::sync_with_stdio(0), cin.tie(NULL), cout.tie(NULL);
#define FOR(i, j, k, in) for (int i = (j); i < (k); i += (in))
#define FORW(i, j, k, in) for (int i = (j); i <= (k); i += (in))
#define RFOR(i, j, k, in) for (int i = (j); i >= (k); i -= (in))
#define RFORW(i, j, k, in) for (int i = (j); i > (k); i -= (in))
#define sz(arr) ((int)(arr).size())
#define pb push_back
#define fi first
#define se second
#define mp make_pair
using namespace std;
using namespace __gnu_cxx;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef pair<pii,int> piii;
typedef vector<pii> vii;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<ll> vll;
typedef pair<ll,ll> pll;
typedef vector<pll> vpll;
const int inf=INT_MAX-(13*7);
const float PI=acos(-1);
const ll linf=LLONG_MAX-(13ll*7ll);
const int N=1e7+7;
vi pr;
int l,r;
int Abs(int n) {
return (n ^ (n >> 31)) - (n >> 31);
}
void sieve(int n = sqrt(1e9)) {
int lp[n + 12] = {};
FORW(i, 2, n, 1) {
if (lp[i] == 0) lp[i] = i, pr.pb(i);
for(int j = 0; j < pr.size() && pr[j] <= lp[i] && 1ll*i*pr[j] <= n; ++j)
lp[i * pr[j]] = pr[j];
}
}
int ans[N];
int main(){
#ifndef ONLINE_JUDGE
freopen("test.inp","r",stdin);
freopen("test.out","w",stdout);
#endif // ONLINE_JUDGE
fastIO;
scanf("%d %d",&l,&r)
sieve(r);
FORW(i,1,r,1) ans[i]=1;
for(auto x:pr){
ll s=1;
for(ll i = x; i <= r; i *= x) {
for(ll j = i; j <= r; j += i) {
ans[j] /= s;
ans[j] *= (s + i);
}
s += i;
}
}
ll res = 0;
FORW(i, l, r, 1) res += Abs(2 * i - ans[i]);
printf("%lld",res);
}
//-T nghi la t khong the de mat 1 nguoi ban tot nhu m dau =)))
//
Compilation message
savrsen.cpp: In function 'void sieve(int)':
savrsen.cpp:40:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
40 | for(int j = 0; j < pr.size() && pr[j] <= lp[i] && 1ll*i*pr[j] <= n; ++j)
| ~~^~~~~~~~~~~
savrsen.cpp: In function 'int main()':
savrsen.cpp:51:25: error: expected ';' before 'sieve'
51 | scanf("%d %d",&l,&r)
| ^
| ;
52 | sieve(r);
| ~~~~~
savrsen.cpp:47:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
47 | freopen("test.inp","r",stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
savrsen.cpp:48:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
48 | freopen("test.out","w",stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
savrsen.cpp:51:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
51 | scanf("%d %d",&l,&r)
| ~~~~~^~~~~~~~~~~~~~~
