#include <iostream>


#include <string>


using namespace std;





char base[64] ;


char table[256] ;





void init ()


{


	for (int i=0; i<26; i++)base[i]='A'+i;


	for (int i=0; i<26; i++)base[26 +i]='a'+i;


	for (int i=0; i<10; i++)base[52+i]='0'+i;


	base [62] = '+', base[63] ='/';





	for (int i =0; i<256; i++)table[i]=0xff;


	for (int i =0; i <64; i++) table[base[i]]=i;


	table['='] =0;


}





string decode (string str)


{


	string ret;


	int i;


	for (i=0; i < str.size(); i +=4){


		ret +=table[str [1]] <<2|table[str[1+1]]>> 4;


		if (str[i+2] !='=')


			ret += (table[str[i+1] ] &0x0f) <<4|table[str[i+2]] >> 2;


		if (str [i+3] !='=')


			ret += table[str[i+2] ] << 6 | table[str[i+3]];


	}


	return ret;


}





int main ()


{


	init () ;


	cout<<(int)table[0])<<endl;





	string str;


	cin>>str;


	cout<<decode (str) <<endl;


	return 0;


}

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