#include <iostream>
#include <math.h>
using namespace std;

unsigned long long  n,b,c,k,m;
long double f,i;
int main ()
{
   cin >>n;
   b=2;
   if (modf(sqrt((double)n),&i)==0) {cout <<(unsigned long long)sqrt((double)n)<<"\n"; cout <<"1"<<"\n";}
   else
   {
   for ( ;b<=n;b++)
   {
      f=modfl(sqrt((long double)n*(double)(b*b*b)),&i);
      if (f==0) break;
   }
    m=(unsigned long long )sqrt((long double)n*(double)(b*b*b));
   cout <<m<<"\n";
   cout <<b<<"\n";
   }
   return 0;
}

Are u crazy? :)

I had WA12 when I wrote v*v for integer v - it overflowed. Perhaps your long double (equals double for VC++) overflows too. Try putting everything into __int64, no floating point. I use prime factorization for that.