#include<bits/stdc++.h>
using namespace std;
class LastDigit
    {
    	int d = 0;
    	long long int f(long long int x)
            {
            	
            	long long int sum = 0;
            	while(x != 0)
                    {
                    	d++;
                    	sum = sum + x;
                    	//cout << sum << " ";
                    	x =x/10;
                    }
            	return sum;
            }
    	public:
    	long long findX(long long S)
            {
            	//return f(900000000000000000);
            	long long int i;
            	f(S);
            	int dig = d;
            	int d1 = dig -1;
            	int ans = -1;
            	double a1 = (double)(pow(10,d1) -1) / (9*pow(10,d1-1));
            	d1++;
            	double a2 = (double)(pow(10,d1) -1) / (9*pow(10,d1-1));
            	a1 = 1/a1;
            	a2 = 1/a2;
            	a1 = S*a1;
            	a2 = S*a2;
            	for(i=a1 - 100 ; i <= a1 + 100 ; i++)
                    if(f(i) - S == (long long )0)
                    return i;
                for(i = a2 - 100 ;i <= a2 + 100 ; i++)
                    if(f(i) - S == (long long )0)
                    return i;
                return ans;
                    
            }
    };
    int main()
    {
    	class LastDigit ld;
    	cout << ld.findX(837592744927492746);
    	return 0;
    }