九度1118...

#include <stdio.h>
#include <string.h>
#include <map>
#include <algorithm>
#include <ctype.h>

using namespace std;

map<char, int> p;
map<int, char> q;

int a, b;
char n[1000];

void init()
{
    for (int i = 0; i < 6; i++)
    {
        p['A' + i] = 10 + i;
        p['a' + i] = 10 + i;
    }

    for (int i = 0; i < 10; i++)
        q[i] = '0' + i;
    for (int i = 0; i < 6; i++)
        q[10 + i] = 'A' + i;
}

int toDemical(char* num)
{
    int sum = 0;
    int len = strlen(num);
    for (int i = 0; i < len; i++)
    {
        if ( isdigit(num[i]) )
            sum = sum * a + num[i] - '0';
        else
            sum = sum * a + p[num[i]];
    }

    return sum;
}

void toB(int d)
{
    if ( d / b >  0 )
        toB( d / b );
    printf("%c", q[d % b]);
}

int main()
{
 //   freopen("1.txt", "r", stdin);

    init();

    while ( scanf("%d%s%d", &a, n, &b) == 3 )
    {
        int tmp = toDemical(n);
        toB(tmp);
        printf("\n");
    }

    return 0;

}