Опсег

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

public class Range {
     static long s(long x)
        {
            long suma=0;
            while(x != 0){
                 long t = x%10;
                 suma+=t;
                 x/=10;
                }
            return suma;
        }

    static long proveri(long N, long A, long B) {
        // Vasiot kod tuka
        if(A==B) return -1;
        if((A*A)+s(A)+(200*A) == N)return A;
        if((B*B)+s(B)+(200*B) == N )return B;

      long i;
      long mid = (A+B)/2;
      long temp =  (mid*mid) + s(mid) + (200*mid);
      if(temp == N)return mid;
      else if(temp > N ){
          return proveri(N,A,mid);
      }
        else if(temp<N){
           return proveri(N,mid,B);

      }
      return -1;

    }

    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());
        long A = Long.parseLong(st.nextToken());
        long B = Long.parseLong(st.nextToken());

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

        br.close();

    }
}