#include<bits/stdc++.h>
using namespace std;
char c[18]="0123456789ABCDEF";
int shuma[255];
int n,m,d;
string s;
stack<int> mjz;
int main()
{
	scanf("%d\n",&n);
	for(int i='0';i<='9';i++)
		shuma[i]=i-'0';
	shuma['A']=10;shuma['B']=11;shuma['C']=12;shuma['D']=13;
	shuma['E']=14;shuma['F']=15;
	getline(cin,s);
	scanf("%d",&m);
	for(int i=0,j=s.size()-1;j>=0;i++,j--)
		d+=pow(n,i)*shuma[s[j]];
	while(d!=0)
	{
		mjz.push(d%m);
		d/=m;
	}
	while(!mjz.empty())
	{
		printf("%c",c[mjz.top()]);
		mjz.pop();
	}
	return 0;
}

rt，代码大概是这样，0pts