#include <stdio.h>

int F(int H, int S)
{
	if (H == 1)
		return 0;
	if (S == 1)
		return H-1;
	if (H <= S)
		return (F(H-1,S) + S) % H;
	int k = H/S;
	int z = H%S;
	int f = F(H-k,S);
	if (f <= z)
		return (f + k*S) % H;
	else
		return (f + k*S + (f-z)/(S-1)) % H;
}

int main(void) {
        int H, S;
        scanf("%d%d", &H, &S);
        printf("%d\n", F(H,S)+1);
        return 0;
}