#include<string>
#include<iostream>
#include<stdlib.h>
#include<cstdio> 
using namespace std;
bool isHW(char* s){
	string temp;
	for(int i=0;s[i]!='\0';i++){
		temp.push_back(s[i]);
	}
	for(int i=0,j=temp.size()-1;i<j;i++,j--){
		if(temp[i]!=temp[j])return false;
	}
	return true;
}
int add(int n){
	int temp=n;
	int sum=0;
	while(temp!=0){
		sum=sum*10+temp%10;
		temp/=10;
	}
	return sum+n;
}
int main(){
	char s[200];
	int n,m;
	cin>>n>>m;
	int count=0;
	while(count<=30){
		itoa(m,s,n);
		if(isHW(s))break;
		m=add(m);
		count++;
	}
	if(count>30)cout<<"impossible!";
	else cout<<"STEP="<<count;
	return 0;
}