#include <stdio.h>
int main()
{
	int n, m, k;
	char data[10010];
	while(scanf("%d%d%d", &n, &m, &k) != EOF)
	{
		int res = 0;
		long long x = (long long)k * (m + 1);
		while(x >= 0)
		{
			if(x && x % (m + 1) == 0) res++;
			x -= x / (m + 1) + n;
		}
		scanf("%s", data);
		printf("%c\n", (data[x + n] - 'A' + res) % 26 + 'A');
	}
	return 0;
}