my code:
#include<iostream>
#include<cmath>
using namespace std;
main()
{
    unsigned int n,temp,nc;
    cin>>n;
    nc=n;
    temp=sqrt(n);
    if(n==0)
    cout<<0;
    else if(temp*temp==n)
    cout<<1;
    else
    {
        unsigned int x=-1,m=0,q=4,t;
        for(unsigned int i=temp;i>=1;i--)
        {
            t=i;
            while(x!=0)
            {
                x=n-t*t;
                n=x;
                t=sqrt(x);
                m++;
            }
        if(m<q)
            q=m;
        if(m==2)
            break;
        x=-1;
        m=0;
        n=nc;
        }
        cout<<q;
    }
}