LYDSY 1257
题目大意
暂无
题目解法
暂无
RTFC
#include <cstdio>
long long n, k, ans;
int main()
{
scanf("%lld%lld", &n, &k);
long long sz = n < k ? n : k;
for (long long i = 1, last, t; i <= sz; i = last + 1)
{
t = k / i, last = k / t;
if (last >= n) last = n;
ans -= ((last - i + 1) * (i + last) >> 1) * t;
}
printf("%lld", ans + n * k);
}