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

int main(){
    long long int EW, NS;
    long long int dt, cnt = 0;

    scanf("%lld %lld %lld", &EW, &NS, &dt);
    if(NS >= 0 && EW != 0){
        cnt++;
    }else if(NS < 0){
        cnt += 2;
    }else if(NS == 0 && EW == 0){
        ;
    }
    if(NS%dt == 0){
        cnt += llabs(NS)/dt;
    }else{
        cnt += llabs(NS)/dt + 1;
    }

    //if(EW != 0) cnt++;
    if(EW%dt == 0){
        cnt += llabs(EW)/dt;
    }else{
        cnt += llabs(EW)/dt + 1;
    }

    printf("%lld\n", cnt);

    return 0;
}