#include <cstdio>
#include <algorithm>

int main(){
    int X, Y, L;
    scanf("%d %d %d", &X, &Y, &L);

    int res;
    if(X == 0){
        res = (std::abs(Y) + L - 1) / L + (Y>=0?0:2);
    }else if(Y == 0){
        res = (std::abs(X) + L - 1) / L + (X==0?0:1);
    }else{
        res = (std::abs(Y) + L - 1) / L + (std::abs(X) + L - 1) / L;
        if(X > 0 && Y > 0){
            res += 1;
        }else if(X > 0 && Y < 0){
            res += 2;
        }else if(X < 0 && Y > 0){
            res += 1;
        }else{
            res += 2;
        }
    }

    printf("%d\n", res);
}