#include <stdio.h>
int main(void) {
double m, n, x;
int i, time, j;
while(scanf("%lf%lf", &m, &n) != EOF) {
time = x = 0;
for(i = 1;x < m;i++) {
for(j = 1;j <= i && x < m;j++) {
time++;
x += n;
}
}
printf("%d\n", time + i - 2);
}
return 0;
}