#include<stdio.h>

int main(){
    // 宣言
    int controlCnt = 0;
    signed int X = 0;
    signed int Y = 0;
    signed int distance = 0;
    
    // 入力値受け取り
    scanf("%d", X);
    scanf("%d", Y);
    scanf("%d", distance);
    
    // X方向
    if(X >= 0){
        controlCnt++;
        controlCnt += X / distance + (X % distance > 0);
        if(Y == 0)
            goto answer;
        
    }else{
        controlCnt += 2;
        controlCnt += -X / distance + (-X % distance > 0);
        if(Y == 0)
            goto answer;
    }
    
    // Y方向
    if(Y > 0)
        controlCnt += Y / distance + (Y % distance > 0);
    else
        controlCnt += -Y / distance + (-Y % distance > 0);
    goto answer;
    
    // 回答表示
answer:
    printf("%d",controlCnt);
    return 0;
}