#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main(){
    int x, y, l, lx, ly, rotFlag;
    scanf("%d %d %d", &x, &y, &l);
    lx = (int)ceil( (double)abs(x)/l );
    ly = (int)ceil( (double)abs(y)/l );
    if(y < 0) rotFlag = 2;
    else if(x == 0) rotFlag = 0;
    else rotFlag = 1;
    printf("%d\n", lx + ly + rotFlag);

    return 0;
}