poj 1183 反正切函数的应用

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <cmath>using namespace std;int main(){    long long a;    scanf("%lld", &a);    long long ans;    for (ans = a; (a * a +1) % ans; ans--);    printf("%lldn", ans +2* a + (a * a +1) / ans);    return 0;}