#include <bits/stdc++.h>
using namespace std;
const int N=0x3f3f3f3f;
string s;
int a[200005];
struct bigint
{
	string s;
	int r;
	friend bigint operator + (const bigint a,const bigint b)
	{
		string s1=a.s,s2=b.s;
		reverse(s1.begin(),s1.end());
		reverse(s2.begin(),s2.end());
		int shu1[10050],shu2[10050],ans[10050];
		memset(shu1,0,sizeof(shu1));
		memset(shu2,0,sizeof(shu2));
		memset(ans,0,sizeof(ans));
		int len1=s1.size(),len2=s2.size();
		for(int i=0;i<len1;i++) shu1[i]=int(s1[i]-48);
		for(int i=0;i<len2;i++) shu2[i]=int(s2[i]-48);
		int len=max(len1,len2);
		for(int i=0;i<len;i++)
		{
			ans[i]+=shu1[i]+shu2[i];
			if(ans[i]>=10)
			{
				ans[i+1]++;
				ans[i]=ans[i]%10;
			}
		}
	    if(ans[len]!=0) len++;
	    while(ans[len-1]==0&&len>1) len--;
		bigint lin;
	    lin.s="";
	    for(int i=len-1;i>=0;i--) lin.s+=char(ans[i]+48);
	    return lin;
	}
};
int main() 
{
	bigint m,k;
	int n,ans=0;
	cin>>n>>m.s;
	for(int i=1;i<=30;i++)
	{
		ans++;
		k.s=m.s;
		reverse(k.s.begin(),k.s.end());
		m.s=(m.s+k.s);
		int len=m.s.size();
		bool flag=true;
		for(int j=0;j<len;j++)
		{
			if(m.s[j]!=m.s[len-j])
			{
				flag=false;
				break;
			}
		}
		if(flag==true)
		{
			cout<<"STEP="<<ans;
			return 0;
		}
	}
	return 0;
}