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

int main(void){
    int cnt = 0, X, Y, L;
    scanf("%d %d %d", &X, &Y, &L);

    if(Y>0){
        if(Y%L==0){
            cnt += Y/L;
        }else{
            cnt += Y/L + 1;
        }
        if(X!=0){
            cnt++;
            if(abs(X)%L==0){
                cnt += abs(X)/L;
            }else{
                cnt += abs(X)/L + 1;
            }
        }
    }else if(Y==0){
        if(X!=0){
            cnt++;
            if(X%L==0){
                cnt += X/L;
            }else{
                cnt += X/L + 1;
            }
        }
    }else{
        cnt += 2;
        if(abs(Y)%L==0){
            cnt += abs(Y)/L;
        }else{
            cnt += abs(Y)/L + 1;
        }
        if(X!=0){
            if(abs(X)%L==0){
                cnt += abs(X)/L;
            }else{
                cnt += abs(X)/L + 1;
            }
        }
    }
    printf("%d\n", cnt);
    return 0;
}