#include <stdio.h>

main() {
    int X, Y, L;
    int count = 0;
    
    scanf("%d", &X);
    scanf("%d", &Y);
    scanf("%d", &L);
    
    if (Y >= 0) {
        if (X == 0) {
            count = 0;
        } else {
            count = 1;
        }
    } else if (Y == 0) {
        count = 1;
    } else if (Y < 0) {
        count = 2;
    }

    if (X < 0)
        X = -X;
    if (Y < 0)
        Y = -Y;

    count += Y/L;
    if (Y%L > 0)
        count++;
    
    count += X/L;
    if (X%L > 0)
        count++;
        
    printf("%d\n", count);
}