Reorganizare 2- formula

#include <fstream>
using namespace std;

ifstream cin("reorganizare2.in");
ofstream cout("reorganizare2.out");

int main()
{
    long long n,inceput,sfarsit,put,cif,ccif;
    cin>>n;
    inceput=(n-1)*n/2+1;
    sfarsit=n*(n+1)/2;
    ///prima parte
    put=9;
    cif=1;
    while(put*cif<=inceput){
        inceput-=put*cif;
        put*=10;
        cif++;
    }
    ccif=(inceput-1)%cif+1;
    inceput=put/10+inceput/cif;
    ccif++;
    while(ccif<cif){
        inceput/=10;
        ccif++;
    }
    cout<<inceput%10<<" ";
    ///a doua parte
    put=9;
    cif=1;
    while(put*cif<=sfarsit){
        sfarsit-=put*cif;
        put*=10;
        cif++;
    }
    ccif=(sfarsit-1)%cif+1;
    sfarsit=put/10+sfarsit/cif;
    while(ccif<cif){
        sfarsit/=10;
        ccif++;
    }
    cout<<sfarsit%10;
    ///printf("%d ",sfarsit%10);
    return 0;
}