/* Obtained from http://www.kdn.gr.jp/~shii/programming/unbase64.c
   2007-01-25 */

#include <stdio.h>

void main() {
	int i,dat,a,restBit=8,prevBit = 0;
	while( !feof(stdin) ) {
		a = fgetc(stdin);
		if ( a == '=' ) break;
		if (a >= 'A' && a <= 'Z')
			a -= 'A';
		else if (a >= 'a' && a <= 'z')
			a = a - 'a' + 26;
		else if (a >= '0' && a <= '9')
			a = a - '0' + 52;
		else if (a == '+')
			a = 62;
		else if (a == '/')
			a = 63;
		else continue;
		if (restBit > 6) {
			prevBit = (prevBit<<6) | a;
			restBit -= 6;
		} else {
			dat = (prevBit << restBit) | ((a >> (6-restBit)) & 0x3f);
			restBit = 2+restBit;
			prevBit = a;
			fputc(dat,stdout);
		}
	}
}