Range, Опсег Аипс

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Range {


    static int proveri(long N, int A, int B) {

        long rez = 0L;
        if( B > Math.sqrt( (double)N ) )
            B = ( int )Math.sqrt( (double)N );

        // ako e ocigledno deka br x e 10 na stepen, zbirot na cifrite na n ke e 4

        if( zbirCifri( N ) == 4 ) {

            for( int i = 1; i<= B; i = i*10 ) {
                rez = (long)i*i + zbirCifri( (long)i ) + (long)200 * i;

                if (rez == N)
                    return i;
            }
        }

        for( int i = A; i<= B; i++) {

            rez = (long) Math.pow( i, 2 ) + zbirCifri( i ) + 200 * i ;
            if( rez == N)
                return i;
        }

        return -1;
    }

    static int zbirCifri( long x ) {

        int zbir = 0;
        while(x > 0) {
            zbir += x % 10;
            x = x / 10;
        }
        return zbir;
    }



    public static void main(String[] args) throws Exception {
        int i,j,k;

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        long N = Long.parseLong(br.readLine());

        StringTokenizer st = new StringTokenizer(br.readLine());
        int A = (int)Long.parseLong(st.nextToken());
        int B = (int)Long.parseLong(st.nextToken());

        int res = proveri(N, A, B);
        System.out.println(res);

        br.close();

    }

}