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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. using ll = long long;
  4.  
  5. int main() {
  6.     ios::sync_with_stdio(false);
  7.     cin.tie(NULL);
  8.  
  9.     ll N, R;
  10.     cin >> N >> R;
  11.     ll ans = 0;
  12.  
  13.     // Enumerate divisor pairs (x, y) of R with x < y
  14.     for (ll x = 1; x * x <= R; ++x) {
  15.         if (R % x == 0) {
  16.             ll y = R / x;
  17.             if (x < y && __gcd(x, y) == 1) {
  18.                 // For each valid (x, y), g can be 1..floor(N / y)
  19.                 ans += N / y;
  20.             }
  21.         }
  22.     }
  23.  
  24.     cout << ans;
  25.     return 0;
  26. }
  27.  
Success #stdin #stdout 0.01s 5308KB
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https://ideone.com/a6Z5MQ
language:
C++ (gcc 8.3)
created:
10 hours ago
visibility:
public

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