mirror of
https://git.sb/baoshuo/OI-codes.git
synced 2024-09-19 22:05:24 +00:00
18 lines
439 B
C++
18 lines
439 B
C++
#include <bits/stdc++.h>
|
|
|
|
using namespace std;
|
|
|
|
int main() {
|
|
long long n, m, ans;
|
|
cin >> n >> m;
|
|
n++, m++;
|
|
ans = n * m * (n * m - 1) * (n * m - 2) / 6 - n * m * (m - 1) * (m - 2) / 6 - m * n * (n - 1) * (n - 2) / 6;
|
|
for (long long i = 1; i <= n; i++) {
|
|
for (long long j = 1; j <= m; j++) {
|
|
ans -= 2ll * (__gcd(i, j) - 1) * (n - i) * (m - j);
|
|
}
|
|
}
|
|
cout << ans << endl;
|
|
return 0;
|
|
}
|