Uva-10311

#include<bits/stdc++.h>
using namespace std;
using ll= long long;
#define pb push_back

vector<ll>prime,v;
bool mark[100000009];

void sieve()
{
    ll n=100000000;
    prime.pb(2);
    mark[0]=1;
    mark[1]=1;

    for(ll i=4; i<=n; i+=2)
        mark[i]=1;

    for(ll i=3; i<=n; i+=2)
    {
        if(!mark[i])
        {
            prime.pb(i);
            if(i*i<=n)
            {
                for(ll j=i*i; j<=n; j+=i*2)
                    mark[j]=1;
            }
        }
    }
}

int main()
{
    sieve();
    ll n,x,i,j;
    while(cin>>n)
    {
        ll ans=1e9,ans1,ans2;
        for(i=0; i<=n; i++)
        {
            if(mark[i]==0 && mark[n-i]==0 && i!=(n-i))
            {
                ll p=abs((n-i)-i);
                if(p<ans)
                {
                    ans=p;
                    ans1=min(n-i,i);
                    ans2=max(n-i,i);
                }
            }
        }

        if(ans!=1e9)
            printf("%lld is the sum of %lld and %lld.\n",n,ans1,ans2);
        else
            printf("%lld is not the sum of two primes!\n",n);
    }


    return 0;
}