#include <stdio>

// TODO: Not done.

int main()
{
    char[] l = "Aa0+/="; // Lookup table.
    int    i = 0;        // Index into lookup table.
    int    c = 0;        // Value of the current byte.
    int    v = 0;        // Value of the current cluster.
    int    n = 0;        // Number of bytes in the current cluster.
    // Get the new value.
    while (n < 3 && (c = getchar()) != EOF) { v = 256 * v + c; ++n; }
    if (c == EOF) break;
    i  = v % 64; v /= 64;
    c  = i % 26; i /= 26;
    if (i == 2) { i += c / 10; c = c % 10; }
    if (i == 3) { i += c;      c = 0;      }
    putchar(l[i] + c);
}