25分10以上无法判断，求助！！

#include<bits/stdc++.h>
using namespace std;
int n,t,ans;
string s;
int change(string s){
    int sum=0,cnt=0;
    for(int i=0;i<s.size();i++){
        sum=0;
        if(s[i]<='9'&&s[i]>='0'){
            sum=(int)(s[i]-'0');
        }
        if(s[i]<='F'&&s[i]>='A'){
            sum=(int)(s[i]-'A'+10);
        }
        cnt+=sum*pow(n,s.size()-i-1);
    }
    return cnt;
}
string get(int x){
    string answer;
    while(x!=0){
        if(x%n>=10){
            answer+=char(x%n+'A'-10);
        }
        else{
            answer+=char(x%n+'0');
        }
        x/=n;
    }
    return answer;
}
bool check(int x){
    int y=0,a=x;
    while(x!=0){
        y=y*10+x%10;
        x/=10;
    } 
    if(y==a) return 1;
    return 0;
}
int main(){
    cin>>n>>s;
    for(int i=1;i<=30;i++){
        t=change(s);
        int t1=t,q=0;
        while(t1!=0){
            q=q*10+t1%10;
            t1/=10;
        }
        t=t+q;
        if(check(t)==1){
            printf("STEP=%d",i);
            return 0;
        }
        s=get(t);
    }
    cout<<"Impossible!";
    return 0;
}