#include <stdio.h>
int main(void){
    int x, y, l;
    int cnt_turn = 0;
    int cnt_move = 0;
    scanf( "%d", &x );
    scanf( "%d", &y );
    scanf( "%d", &l );
    int disx = ( x < 0 ) ? x * -1 : x;
    int disy = ( y < 0 ) ? y * -1 : y;
    
    // 向き変更
    if( x == 0 ){
        // 直進のみ
    }else if( y > 0 ){
        cnt_turn += 1;
    }else{
        cnt_turn += 2;
    }
    
    // x移動
    if( disx == 0 ){
        // 動かない
    }else if( disx <= l ){ 
        cnt_move += 1;
    }else{ 
        cnt_move += ( ( disx / l  ) + ( disx % l == 0 ? 0 : 1 ) );
    }

    // y移動
    if( disy == 0 ){
        // 動かない
    }else if( disy <= l ){ 
        cnt_move += 1;
    }else{
        cnt_move += ( ( disy / l ) + ( disy % l == 0 ? 0 : 1 ) );
    }

    printf( "%d\n", cnt_turn + cnt_move );
    
}